Heat accumulator, method for manufacturing heat accumulator, and vehicle-mounted thermal system including accumulator

ABSTRACT

In an accumulator including a vacuum heat-insulating layer  2  at the outer periphery of a liquid reserving portion  1 , the liquid reserving portion  1  and the vacuum heat-insulating layer  2  are formed by stacking a plurality of tank constituting elements  10  composed of plate members of an identical cross-sectional shape. The liquid reserving portion  1  is composed of liquid reserving portion spaces  10   f  made to communicate by stacking the tank constituting element  10 . The vacuum heat-insulating layer  2  is composed of heat insulating layer space  10   e  which are made to communicate by stacking the tank constituting elements  10  and are evacuated. The openings of the stacked tank constituting elements  10  at the both ends are closed with inlet and outlet cover plates  8  and  9.

TECHNICAL FIELD

The present invention relates to a heat accumulator employed in anengine coolant circulation circuit or the like in order to accelerateengine warm up or to increase the heating performance, and relates to amethod for manufacturing the heat accumulator and a vehicle-mountedthermal system including the same.

BACKGROUND ART

A known conventional heat accumulator which stores engine coolant andkeeps the heat thereof is a heat accumulator having a double structureof metallic inner and outer containers in which the gap between thecontainers is evacuated for thermal insulation (for reference, seePatent Document 1).

In a vehicle-mounted thermal system including the conventional heataccumulator, engine coolant which becomes hot while the vehicle isrunning is taken into the heat accumulator, and the hot engine coolantis stored in the heat accumulator and is kept warm while the vehicle isstopped. At the next start of the engine, the hot engine coolant in theheat accumulator is fed to the engine and a heater core for a passengercompartment heater and used in quick engine warm up and quick heating.

Patent Document 1: Japanese Patent Application Publication No.2004-20027 DISCLOSURE OF THE INVENTION Problems to be Solved by theInvention

However, the conventional heat accumulator is composed of the inner andouter containers formed by drawing metallic plates. Accordingly, whenthere is a need to change necessary capacity of the heat accumulator forthe purpose of application to different types of vehicles or the like,the conventional heat accumulator cannot respond to the change innecessary capacity. It is therefore necessary to change the processingdie or make a new processing die, thus causing an increase in cost, aloss for setup at manufacturing, and the like.

Moreover, in manufacturing the conventional heat accumulator, metallicplates are drawn and welded into main components of the inner and outercontainers. The inner and outer containers are joined to othercomponents with a space between the containers, and then the componentsare fixed by welding or the like, so that a container is manufactured.After the container is manufactured, evacuation is performed for thecontainer to form a vacuum heat-insulating layer at an entirelydifferent process, thus manufacturing the heat accumulator. When theevacuation is performed in the air atmosphere using a vacuum pump at theevacuation step, the degree of vacuum of the vacuum heat-insulatinglayer varies for each product. In addition, the fixing step of fixingthe components and the evacuation step of forming the vacuumheat-insulating layer are performed at the steps entirely different fromeach other, and it takes a great deal of labor hours and efforts tomanufacture the heat accumulator.

Furthermore, in the vehicle-mounted thermal system including theconventional heat accumulator, at the start of the engine, during thefirst cycle of circulation cycles of the engine coolant, hot enginecoolant is fed to the engine or the heater core of the passengercompartment heater, but during and after the second cycle, the hotengine coolant is affected by temperature of a system environmentincluding the engine, air, and the like and moreover is mixed with coldengine coolant. Accordingly, the hot coolant has heat instantly removed,and the cold engine coolant starts to circulate. Accordingly, the quickwarm-up performance of the engine and quick heating performance in thepassenger compartment cannot meet the expectations.

The present invention has been made in the light of the aforementionedproblems, and a first object of the present invention is to provide aheat accumulator capable of easily responding a request for changing thenecessary capacity without an increase in cost by just increasing ordecreasing the number of stacked tank constituting elements.

A second object of the present invention is to provide a method ofmanufacturing a heat accumulator which is capable of forming a vacuumheat-insulating layer having an unvarying and stable vacuum quality andis capable of simplifying the process to reduce the manufacturingefforts and shorten the manufacturing time.

Another object is to provide a compact heat accumulator having high heatstorage performance. Moreover, a third object of the present inventionis to provide a vehicle-mounted thermal system including a heataccumulator which is capable of achieving acceleration of engine warm-upand an increase in heating performance in the passenger compartmentmeeting expectations at the start of the power unit with a simple heatmedium circulation control.

Means for Solving the Problems

To accomplish the aforementioned first object, according to the presentinvention, a heat accumulator includes: a heat-insulating layer at theouter periphery of a liquid reserving portion, in which the liquidreserving portion and heat insulating layer are formed by stacking aplurality of tank constituting elements composed of plate members of anidentical cross-sectional shape.

To accomplish the aforementioned second object, according to the presentinvention, a method of manufacturing a heat accumulator including avacuum heat-insulating layer at the outer periphery of a liquidreserving portion includes: a part processing step of processingconstituent parts constituting the heat accumulator; a temporaryassembly step of assembling the processed constituent parts into acontainer; and a brazing step of evacuating the temporarily assembledcontainer in a furnace and increasing temperature of the furnace tobraze the constituent parts into a unit in vacuum atmosphere.

To achieve the aforementioned third object, according to the presentinvention, in a vehicle-mounted thermal system including a heataccumulator, the vehicle-mounted thermal system including: avehicle-mounted heat source heating a heat medium while a power unit isbeing driven; a vehicle-mounted heat demand source requiring a hot heatmedium when the power unit starts from a stopped state where temperatureof the heat medium decreases; and a heat medium circuit connecting thevehicle-mounted heat source and the vehicle-mounted heat demand source,in which the heat medium circuit is provided with the heat accumulatorwhose inlet is connected to the vehicle-mounted heat source and whoseoutlet is connected to the vehicle-mounted heat demand source; the heataccumulator includes a heat storage layer between a liquid reservingportion and a heat-insulating layer; the heat storage layer being filledwith a heat storage material absorbing and releasing heat along with itsphase transition between liquid and solid phases; a circuit connectingthe vehicle-mounted heat source and the inlet of the heat accumulator isprovided with a first valve; a circuit connecting the vehicle-mountedheat demand source and the outlet of the heat accumulator is providedwith a second valve; and the heat accumulator includes heat mediumcirculation control means which opens the first and second valves whilethe power unit is being driven, closes the first and second valves whenthe power unit stops, and opens the first and second valves when thepower unit starts.

EFFECTS OF THE INVENTION

According to the heat accumulator of the present invention, it ispossible to satisfy the request to change the necessary capacity by onlyincreasing or decreasing the number of the stacked tanks constitutingelements composed of the plate members of an identical cross-sectionalshape. Specifically, in the case of a heat accumulator having astructure composed of an inner and outer containers manufactured bydrawing and the like, changing the necessary capacity of the heataccumulator requires replacing a drawing die or producing a new drawingdie, thus leading to an increase in cost, a loss at manufacturing setup,or the like.

On the other hand, in the present invention, the heat accumulator has astacking structure including the plurality of tank constituting elementsstacked on each other. Accordingly, it is possible to immediately changethe capacity from a certain capacity to a different capacity in theminimum unit equivalent to the capacity of the single tank constitutingelement if a plurality of tank constituting elements are prepared inadvance. Accordingly, the request to change the necessary capacity issatisfied by increasing or decreasing the number of stacked tankconstituting elements. Consequently, the request to change the necessarycapacity is easily satisfied by only increasing or decreasing the numberof stacked tank constituting elements without increasing the cost.

According to the method of manufacturing a heat capacity, in the partprocessing step, the constituent parts constituting the heat accumulatorare processed, and in the temporary assembly step, the processedconstituent parts are assembled into a container. In the brazing step,the temporarily assembled container is evacuated in a furnace andincrease in temperature to braze the constituent parts into a unit inthe vacuum atmosphere. The heat accumulator having a vacuumheat-insulating layer at the outer periphery of the liquid reservingportion is thus manufactured.

In this manner, in the brazing step, by controlling the vacuumatmosphere in the furnace into a stable vacuum atmosphere, compared tothe case of evacuation in the air atmosphere under individual control,the vacuum heat-insulating layer having stable and unvarying vacuumquality can be formed.

Moreover, in the brazing process, fixation of the parts and evacuationcan be both achieved. Accordingly, compared to the case of evacuatingthe vacuum heat-insulating layer in another process after fixing theparts by welding or the like, the processes can be simplified, and themanufacturing efforts and time can be reduced.

It is therefore possible to form the vacuum heat-insulating layer withunvarying and stable vacuum quality and reduce the manufacturing effortsand time by the simplification of the process.

Furthermore, according to the vehicle-mounted heat system including theheat accumulator of the present invention, while the power unit isdriven, the first and second valves are opened by the heat mediumcirculation control means. Accordingly, when the heat storage materialreceives heat from the hot heat medium passing the heat accumulator fromthe inlet to the outlet and the temperature of the heat storage materialreaches the melting point, the heat storage material changes the phasethereof from the solid to liquid phase and absorbs heat energy duringthe phase transition.

When the power unit stops, the first and second valves are closed by theheat medium circulation control means. The hot heat medium is thenenclosed by the liquid reserving portion surrounded by the two layers ofthe heat-insulating layer and heat storage layer.

Furthermore, when the power unit starts, the first and second valves areopened by the heat medium circulation control means. The hot heat mediumstored is fed to the vehicle-mounted heat demand source during the firstcycle of the circulation cycles of the heat medium. Thereafter, the hotheat medium is affected by the temperature of the system environment andis mixed with cold heat medium. The temperature of the engine coolantwithin the heat accumulator therefore decreases. However, during andafter the second cycle where the temperature of the heat storagematerial decreases to the freezing point because of the decrease intemperature of the heat medium, the heat storage material changes thephase thereof from the liquid to the solid phase. The heat stored in theheat storage material is released along with this phase transition. Thedecrease in temperature of the heat medium is prevented by the heatreleased from the heat storage material, and the heat medium kept hot isfed to the vehicle-mounted heat demand source.

Consequently, with such a simple heat medium circulation control, at thestart of the power unit, it is possible to, for example, when thevehicle-mounted heat demand source is an engine, achieve expectedwarm-up promotion of the engine and, when the vehicle-mounted heatdemand source is a heater core, achieve an expected increase inpassenger compartment heating performance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical-sectional front view showing a heat accumulator ofEmbodiment 1 of the present invention.

FIG. 2 is an enlarged view of part A of FIG. 1 showing the heataccumulator of Embodiment 1.

FIG. 3 is an external perspective view showing the heat accumulator ofEmbodiment 1.

FIG. 4 is a sectional perspective view showing the heat accumulator ofEmbodiment 1.

FIG. 5 is an exploded perspective view showing the heat accumulator ofEmbodiment 1.

FIG. 6 is a process diagram showing vacuum brazing of a heat accumulatorS1 of Embodiment 1.

FIG. 7 is a vertical-sectional front view showing a heat accumulator ofEmbodiment 2.

FIG. 8 is an enlarged view of part B of FIG. 7 showing the heataccumulator of Embodiment 2 of the present invention.

FIG. 9 is an external perspective view showing the heat accumulator ofEmbodiment 2.

FIG. 10 is a sectional perspective view showing the heat accumulator ofEmbodiment 2.

FIG. 11 is an exploded perspective view showing the heat accumulator ofEmbodiment 2.

FIG. 12 is a process diagram showing vacuum brazing of a heataccumulator S2 of Embodiment 2.

FIG. 13 is a view showing an air groove of the heat accumulator S2 ofEmbodiment 2, which is provided for increasing the degree of vacuum at abrazing step in a furnace.

FIG. 14 is an explanatory view showing a heat storage materialencapsulation process in the vacuum brazing of the heat accumulator S2of Embodiment 2.

FIG. 15 is an engine coolant circulation circuit diagram showing a firstexample of the engine coolant circulation system including the heataccumulator S2 of Embodiment 2.

FIG. 16 is an engine coolant circulation circuit diagram showing asecond example of the engine coolant circulation system including theheat accumulator S2 of Embodiment 2.

FIG. 17 is a coolant circulation circuit diagram showing a first exampleof an electrical equipment coolant circulation system for a drivingmotor including the heat accumulator S2 of Embodiment 2.

FIG. 18 is a coolant circulation circuit diagram showing a secondexample of an electrical equipment coolant circulation system for adriving motor including the heat accumulator S2 of Embodiment 2.

FIG. 19 is a vertical-sectional front view showing a heat accumulatormanufactured by a manufacturing method of Embodiment 3 of the presentinvention.

FIG. 20 is an enlarged view of part C of FIG. 19 showing the heataccumulator manufactured by the manufacturing method of Embodiment 3.

FIG. 21 is an external perspective view showing the heat accumulatormanufactured by the manufacturing method of Embodiment 3.

FIG. 22 is a sectional perspective view showing the heat accumulatormanufactured by the manufacturing method of Embodiment 3.

FIG. 23 is an exploded perspective view showing the heat accumulatormanufactured by the manufacturing method of Embodiment 3.

FIG. 24 is an operation explanatory view explaining a heat storingoperation and a heat releasing operation in the heat accumulator ofEmbodiment 3.

FIG. 25 is an engine coolant temperature comparative characteristicdiagram at the start of the engine for cases without a heat accumulator,with a conventional heat accumulator, and with the heat accumulator ofEmbodiment 3.

FIG. 26 is an engine coolant circulation circuit diagram showing anengine coolant circulation system (an example of a vehicle-mountedthermal system) including the heat accumulator S of Embodiment 4 of thepresent invention.

FIG. 27 is an explanatory view of an engine coolant circulationoperation in the engine coolant circulation system of Embodiment 4.

FIG. 28 is an engine coolant circulation circuit diagram showing anengine coolant circulation system (an example of the vehicle-mountedthermal system) including the heat accumulator S of Embodiment 5 of thepresent invention.

FIG. 29 is an explanatory view of an engine coolant circulationoperation in the engine coolant circulation system of Embodiment 5.

FIG. 30 is a coolant circulation circuit diagram showing an electricalequipment coolant circulation system for a driving motor (an example ofthe vehicle-mounted thermal system) including the heat accumulator S ofEmbodiment 6 of the present invention.

FIG. 31 is an explanatory view of a coolant circulation operation in theelectrical equipment coolant circulation system for a driving motor ofEmbodiment 6.

FIG. 32 is a coolant circulation circuit diagram showing an electricalequipment coolant circulation system for a driving motor (an example ofthe vehicle-mounted thermal system) including the heat accumulator S ofEmbodiment 7 of the present invention.

FIG. 33 is an explanatory view of a coolant circulation operation at theelectrical equipment coolant circulation system for a driving motor ofEmbodiment 7.

EXPLANATION OF REFERENCE SYMBOLS AND NUMERALS

-   S1: HEAT ACCUMULATOR-   1: LIQUID RESERVING PORTION-   2: VACUUM HEAT-INSULATING LAYER (HEAT-INSULATING LAYER)-   6: INLET PIPE-   7: OUTLET PIPE-   8: INLET COVER PLATE-   9: OUTLET COVER PLATE-   10 a: FIRST PARTITION WALL-   10 b: SECOND PARTITION WALL-   10 c: INNER RIB-   10 d: OUTER RIB-   10 e: HEAT-INSULATING LAYER SPACE-   10 f LIQUID RESERVING PORTION SPACE-   10 g: POSITIONING PROTRUSION-   S2: HEAT ACCUMULATOR-   2: SIDE VACUUM HEAT-INSULATING LAYER (HEAT-INSULATING LAYER)-   3: INLET END VACUUM HEAT-INSULATING LAYER (HEAT-INSULATING LAYER)-   4: OUTLET END VACUUM HEAT-INSULATING LAYER (HEAT-INSULATING LAYER)-   15: INLET END PLATE-   16: INLET COVER PLATE-   17: OUTLET END PLATE-   18: OUTLET COVER PLATE-   19: TANK CONSTITUTING ELEMENT-   19 a: FIRST PARTITION WALL-   19 b: SECOND PARTITION WALL-   19 c: THIRD PARTITION PORTION-   19 d: INNER RIB-   19 e: OUTER RIB-   19 f HEAT-INSULATING LAYER SPACE-   19 g: HEAT STORAGE LAYER SPACE-   19 h: LIQUID RESERVING PORTION SPACE-   19 i: POSITIONING PROTRUSION-   19 j: AIR GROOVE-   20: CAP-   21: ENGINE-   22: HEATER CORE-   23: FIRST VALVE-   24: SECOND VALVE-   25: RADIATOR-   26: THERMO VALVE-   27: CIRCULATION PUMP-   28: CONTROLLER-   29: PUMP-   30: INVERTER COOLER-   31: BATTERY COOLER-   S3: HEAT ACCUMULATOR-   38: FIRST CYLINDRICAL SIDE PLATE (CYLINDRICAL MEMBER)-   39: FIRST INLET END PLATE (INLET PLATE MEMBER)-   40: FIRST OUTLET END PLATE (OUTLET PLATE MEMBER)-   41: SECOND CYLINDRICAL SIDE PLATE (CYLINDRICAL MEMBER)-   42: SECOND INLET END PLATE (INLET PLATE MEMBER)-   43: SECOND OUTLET END PLATE (OUTLET PLATE MEMBER)-   44: ACCORDION CYLINDRICAL PLATE (CYLINDRICAL PLATE)

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, a description is given of best modes for implementing aheat accumulator of the present invention based on Embodiments 1 to 7shown in the drawings.

Embodiment 1

First, the constitution is described.

FIG. 1 is a vertical-sectional front view showing a heat accumulator ofEmbodiment 1; FIG. 2 is an enlarged view of part A of FIG. 1 showing theheat accumulator of Embodiment 1; FIG. 3 is an external perspective viewshowing the heat accumulator of Embodiment 1; FIG. 4 is a sectionalperspective view showing the heat accumulator of Embodiment 1; and FIG.5 is an exploded perspective view showing the heat accumulator ofEmbodiment 1.

As shown in FIGS. 1 to 5, a heat accumulator S1 of Embodiment 1 includesa liquid reserving portion 1, a vacuum heat-insulating layer(heat-insulating layer) 2, an inlet pipe 6, an outlet pipe 7, an inletcover plate 8, an outlet cover plate 9, and tank constituting elements10.

The heat accumulator S1 of Embodiment 1 includes the vacuumheat-insulating layer 2 at the outer periphery of the liquid reservingportion 1. The liquid reserving portion 1 and the vacuum heat-insulatinglayer 2 are formed by stacking the plurality of tank constitutingelements 10 which are composed of plate members of an identicalsectional shape.

The heat accumulator S1 of Embodiment 1 includes the inlet and theoutlet cover plate 8 and 9 and the tank constituting elements 10 asconstituent parts. The inlet pipe 6 is fixed to the inlet cover plate 8,and the outlet pipe 7 is fixed to the outlet cover plate 9.

As shown in FIG. 5, each of the tank constituting elements 10 of theheat accumulator S1 of Embodiment 1 includes a first partition wall 10a, a second partition wall 10 b, an inner rib 10 c, and an outer rib 10d coaxially arranged. The first and second partition walls 10 a and 10 bare radially joined at about four places of an entire circumference toform heat-insulating layer spaces 10 e between the joint places. Thespace surrounded by the second partition wall 10 b serves as a liquidreserving portion space 10 f. The inner rib 10 c protrudes from thesecond partition wall 10 b towards the liquid reserving portion 1. Theouter rib 10 d protrudes outward from the first partition wall 10 a andincludes an axially bent portion at a part of the circumference forexterior shape alignment at the stacking. At the joint places betweenthe first and second partition walls 10 a and 10 b, positioningprotrusions 10 g protruding in a tank axis direction are formed (seeFIG. 2).

In the heat accumulator S1 of Embodiment 1, a plurality of the tankconstituting elements 10 are stacked on each other, facing alternatedirections, and the openings of the stacked tank constituting elements10 at the both ends are closed by the inlet and outlet cover plates 8and 9, thus constituting a container.

The liquid reserving portion 1 is composed of the liquid reservingportion spaces 10 f made to communicate with each other by stacking thetank constituting elements 10.

The vacuum heat-insulating layer 2 is formed by evacuating theheat-insulating layer spaces 10 made to communicate with each other bystacking the tank constituting elements 10.

The method of manufacturing the heat insulator S1 of Embodiment 1 is avacuum brazing as follows: Brazing filler metal is applied to theplurality of tank constituting elements 10, and the plurality of tankconstituting elements 10 are stacked on each other. The openings of thestacked tank constituting elements 10 at both ends are closed by theinlet and outlet cover plates 8 and 9, temporarily assembling acontainer. The temporarily assembled container is evacuated in a furnaceand then the temperature is increased.

Next, the operations thereof are described.

[Manufacturing Method of Heat Accumulator]

FIG. 6 is a process diagram showing vacuum brazing for the heataccumulator S1 of Embodiment 1. Hereinafter, the vacuum brazing for theheat accumulator S1 of Embodiment 1 is described using FIG. 6.

Tart Processing Process

In a first part processing process of step S1, the tank constitutingelements 10 are processed by pressing or punching plate materials.

In a second part processing process of step S2, the inlet and outletcover plates 8 and 9 are processed by pressing or punching platematerials.

In a third part processing process of step S3, the inlet and outletpipes 6 and 7 are processed by pipe forming from plate materials,drawing, or the like.

Brazing Filler Metal Applying Process

In a brazing filler metal applying process of step S4, brazing fillermetal is applied to the plurality of tank constituting elements 10 (forexample, stainless steel) processed at the first part processing processof the step S1.

Tart Sub-Assembly Process (Stacking Process)

In a part sub-assembly process of step S5, a desired number of the tankconstituting elements 10 with the brazing filler metal applied theretoin the brazing filler metal applying process of the step S4 are stackedaccording to the designed value of the liquid reserving capacity. In thecase of Embodiment 1, the plurality of tank constituting elements 10 arestacked on each other facing alternate directions so as to provide astack shown in FIGS. 1 to 5.

Assembly Process

In an assembly process of step 6, the stacked tank constituting elements10 assembled in the part sub-assembly process of the step S5 are joinedwith the parts including the inlet and outlet cover plates 8 and 9 andinlet and outlet pipes 6 and 7, which are processed at the second andthird part processing processes of the steps S2 and S3, as shown in FIG.5, to be temporarily built into a container shape as a whole. At thistime, the brazing filler metal is applied to the portions necessary tobe brazed other than the stacked constituting elements 10.

Jig Setting Process

In a jig setting process of step S7, the temporarily fabricatedcontainer is set to a brazing jig so that the individual partstemporarily fabricated into the container shape in the assembly processof the step S6 are not displaced and secure the unity thereof.

Brazing Process

In a brazing process of the step S8, the individual parts are fixed byvacuum brazing at the following in-furnace process.

The in-furnace process includes: an evacuation process to evacuate theinside of the furnace (step S8 a); a warming process to increasetemperature within the furnace (step S8 b); a brazing process to fix theparts with melted brazing filler metal (step S8 c); and a coolingprocess to cool the container fixed by brazing (step S8 d).

Air Sealing Process

In an air sealing process of step S9, the air tightness keeping thevacuum of the vacuum heat-insulating layer 2 of the brazed containertaken out of the furnace is secured.

Shipping Inspection Process

In a shipping inspection process of step S10, shipping inspection ismade in terms of check items including whether the vacuum of the vacuumheat-insulating layer 2 is maintained with no brazing defects.

Tacking Process

In a packing process of step S11, products which pass the shippinginspection are packed.

Shipping Process

In a shipping process of step S12, the packed products are shipped froma factory.

[Heat Storing and Releasing Operation]

In the heat accumulator S1 of Embodiment 1, when a hot heat mediumpassing the liquid reserving portion 1 stops circulating, part of thehot heat medium is enclosed in the liquid reserving portion 1 surroundedby the vacuum heat-insulating layer 2. The heat medium stored in theliquid reserving portion 1 within the heat accumulator S1 is thereforeprevented from cooling and is kept hot.

For using the hot heat medium within the liquid reserving portion 1 ofthe heat accumulator S1, the hot heat medium in the liquid reservingportion 1 is released through the outlet pipe 7. When the hot heatmedium is configured to be released to the engine as hot engine coolantat the start of the engine, the engine warm-up can be accelerated. Whenthe hot heat medium is configured to be released to the heater core atthe start of the engine, the heating performance in the passengercompartment can be increased.

[Operation of Responding to Change in Necessary Capacity]

In the heat accumulator S1 of Embodiment 1, the liquid reserving portion1 and vacuum heat-insulating layer 2 are formed by stacking theplurality of tank constituting elements 10 composed of the plate membersof an identical cross-sectional shape.

Accordingly, the request to change the necessary capacity can besatisfied by increasing or decreasing the number of the stacked tankconstituting elements 10 composed of the plate members of an identicalcross-sectional shape.

Specifically, in the case of a heat accumulator having a structurecomposed of an inner and outer containers manufactured by drawing andthe like as the conventional art, changing the necessary capacity of theheat accumulator requires replacing the drawing die or producing a newdrawing die, thus leading to an increase in cost, a loss atmanufacturing setup, or the like.

On the other hand, in Embodiment 1, the heat accumulator S1 has astacking structure including the plurality of tank constituting elements10 stacked on each other. Accordingly, the request to change thenecessary capacity is satisfied by increasing or decreasing the numberof stacked tank constituting elements 10, and the change of the drawingdie, which increases the cost, is not necessary.

In other words, in the case of Embodiment 1, it is possible toimmediately produce a heat accumulator with a different capacity if aplurality of the tank constituting elements 10 are prepared in advance.When there is a request to increase the necessary capacity with respectto a heat accumulator with a certain capacity, the number of tankconstituting elements 10 stacked is increased. When there is a requestto reduce the necessary capacity, the number of tank constitutingelements 10 stacked is reduced. Herein, the capacity can be changed inunits equivalent to the capacity of the single tank constituting element10.

Next, the effects thereof are described.

According to the heat accumulator S1 of Embodiment 1, the effectsenumerated in the following can be obtained.

(1) In the heat accumulator including the vacuum heat-insulating layer 2in the outer periphery of the liquid reserving portion 1, the liquidreserving portion 1 and vacuum heat-insulating layer 2 are formed bystacking the plurality of tank constituting elements 10 composed of theplate members of an identical cross-sectional shape. It is thereforepossible to easily satisfy the request to change the necessary capacitywithout increasing the cost by just increasing or decreasing the numberof stacked tank constituting elements.(2) The heat accumulator S1 includes the inlet and outlet cover plates 8and 9 and tank constituting elements 10 as the constituent parts. Theinlet pipe 6 is fixed to the inlet cover plate 8, and the outlet pipe 7is fixed to the outlet cover plate 9. Each of the tank constitutingelements 10 includes the first and second partition walls 10 a and 10 bcoaxially arranged. Between the first and second partition walls 10 aand 10 b, the heat-insulating layer space 10 e is formed. The liquidreserving portion space 10 f is surrounded by the second partition wall10 b. The plurality of tank constituting elements 10 are stacked, andthe openings of the stacked tank constituting elements 10 at the bothends are closed by the inlet and outlet cover plates 8 and 9, thusconstituting the container. The liquid reserving portion 1 is composedof the liquid reserving portion spaces 10 f, which are made tocommunicate with each other by stacking the tank constituting elements10, and the vacuum heat-insulating layer 2 is composed of evacuating theheat-insulating layer spaces 10 e, which are made to communicate witheach other by stacking the tank constituting elements 10. It istherefore possible to provide the stacking-type heat accumulator S1which includes the vacuum heat-insulating layer 2 at the outer peripheryof the liquid reserving portion 1 and has high responsiveness to therequest to change the necessary capacity.(3) The heat accumulator S1 is manufactured as follows: The plurality oftank constituting elements 10 are stacked on each other with the brazingfiller metal applied thereto, and the openings of the stacked tankconstituting elements 10 at the both ends are closed with the inlet andoutlet cover plates 8 and 9 to be temporarily assembled. The temporarilyassembled container is subjected to vacuum brazing, which evacuates thetemporarily assembled container within the furnace and then increasesthe temperature thereof. In other words, fixation of the parts andevacuation are both performed at the vacuum brazing process.Accordingly, compared to the case where the parts are fixed by welding,brazing, or the like and then the vacuum heat-insulating layer isevacuated at a different process, it is possible to reduce thevariations in degree of vacuum of the vacuum heat-insulating layer 2 andto shorten the manufacturing time by the simplified process.

According to the method of manufacturing the heat accumulator S1 ofEmbodiment 1, the effects enumerated below can be obtained.

(1) The method of manufacturing the heat accumulator S1 including thevacuum heat-insulating layer 2 at the outer periphery of the liquidreserving portion 1 includes: the part processing processes to processthe constituent parts constituting the heat accumulator S1 (steps S1 toS3); the temporary assembly process to assemble the processedconstituent parts into a container form (step S4 to S6); and the brazingprocess to evacuate the temporarily assembled container within thefurnace and then increase the temperature thereof for brazing theconstituent parts into a unit in the vacuum atmosphere. Accordingly, itis possible to form the vacuum heat-insulating layer 2 with unvaryingand stable vacuum quality and to reduce the manufacturing efforts andtime by the simplified process.(2) The heat accumulator S1 includes the vacuum heat-insulating layer 2at the outer periphery of the liquid reserving portion 1: In the partprocessing processes (steps S1 to S3), the tank constituting elements10, which are composed of plate members having a same cross-sectionalshape and each of which includes the liquid reserving portion space 10 fand vacuum heat-insulating space 10 e, and the inlet and outlet coverplates 8 and 9 are processed. In the temporary assembly process (stepsS4 to S6), the plurality of tank constituting elements 10 are stacked,and the openings of the stacked tank constituting elements 10 are closedwith the inlet and outlet cover plates 8 and 9, thus forming the liquidreserving portion 1 and vacuum heat-insulating layer 2. It is thereforepossible to provide the method of manufacturing the stacking-type heataccumulator S1 which includes the vacuum heat-insulating layer 2 at theouter periphery of the liquid reserving portion 1 and has responsivenessto the request to change the necessary capacity.(3) The temporary assembly process includes the brazing materialapplication process to apply the brazing filler metal to the tankconstituting elements 10 (step S4); the sub-assembly process to stackthe tank constituting elements 10 with the brazing filler metal appliedthereto (step S5); and the assembly process to close the openings of thestacked tank constituting elements 10 with the inlet and outlet coverplates 8 and 9 for fabrication into a container form (step S6).Accordingly, employment of the sub-assembly process to stack the tankconstituting elements 10 with the brazing filler material appliedthereto allows the plurality of stacked tank constituting elements 10 tobe reliably brazed and fixed in the brazing process (step S8).

Embodiment 2

Embodiment 2 is a heat accumulator including a liquid reserving portion,a vacuum heat-insulating layer, and a heat storage layer whileEmbodiment 1 is the heat accumulator including the liquid reservingportion and the vacuum heat-insulating layer.

First, the constitution thereof is described.

FIG. 7 is a vertical-sectional front view showing a heat accumulator ofEmbodiment 2; FIG. 8, an enlarged view of part B of FIG. 7 showing theheat accumulator of Embodiment 2; FIG. 9, an external perspective viewshowing the heat accumulator of Embodiment 2; FIG. 10, a sectionalperspective view showing the heat accumulator of Embodiment 2; and FIG.11, an exploded perspective view showing the heat accumulator ofEmbodiment 2.

As shown in FIGS. 7 to 11, a heat accumulator S2 of Embodiment 2includes a liquid reserving portion 1, a side vacuum heat-insulatinglayer (heat-insulating layer) 2, an inlet end vacuum heat-insulatinglayer 3 (heat-insulating layer), an outlet end vacuum heat-insulatinglayer 4 (heat-insulating layer), a heat storage layer 5, an inlet pipe6, an outlet pipe 7, an inlet end plate 15, an inlet cover plate 16, anoutlet end plate 17, an outlet cover plate 18, and tank constitutingelements 19.

The heat accumulator S2 of Embodiment 2 includes the vacuumheat-insulating layers 2, 3, and 4 at the outer periphery of the liquidreserving portion 1. Between the liquid reserving portion 1 and sidevacuum heat-insulating layer 2, the heat storage layer 5 is provided,which is filled with a heat storage material absorbing or releasing heatduring phase transition between liquid and solid phases.

The heat accumulator S2 of Embodiment 2 includes the inlet and outletend plates 15 and 17, the inlet and outlet cover plates 16 and 18, andthe tank constituting elements 19 as constituent parts. The inlet pipe 6is fixed to the inlet end plate 15, and the outlet pipe 7 is fixed tothe outlet end plate 17.

Furthermore, as shown in FIG. 8, on a third partition wall 19 cseparating a liquid reserving portion space 19 h of each tankconstituting element 19, an inner rib 19 d protruding in a directionorthogonal to the flow of the heat medium from the inlet to the outletis formed. As shown in FIG. 8, the adjacent third partition walls 19 cand 19 c and the adjacent inner ribs 19 d and 19 d abut on each other toform protrusions orthogonal to the flow.

The heat storage material encapsulated in the heat storage layer 5 is aparaffin material as a latent heat storage material. The paraffin rawmaterial stores heat of fusion during phase transition from the solid tothe liquid phase in a temperature range not lower than the melting pointand releases heat of solidification during phase transition from thesolid to the liquid phase in a temperature range not higher than thefreezing point. The heat storage material is paraffin capsules, whichinclude the paraffin material encapsulated in spherical coatings asmicrocapsules. The heat storage layer 5 is filled with aggregates of theparaffin capsules taking an account of a change in volume (about 10%)accompanied with the phase transition between the liquid and solidphases.

Herein, the reason for using the paraffin material as the heat storagematerial is that the phase transition temperature including the meltingpoint (melting temperature) and freezing point (freezing temperature)can be set in a wide range of temperature (−50 to 80° C.) depending onthe number of carbon chains and moreover that the amount of stored heat(latent heat of fusion) thereof is about 130 to 250 kJ/kg, which ishigher than those of the other materials.

For example, in the case of using the heat accumulator in avehicle-mounted thermal system circulating engine coolant to the heatercore, the phase transition temperature is preferably about 50 to 60° C.or more. The reason therefor is that the temperature of the enginecoolant does not always reach 80° C. in winter or some cases. Moreover,the air outlet temperature feeling warm is 30° C., and the phasetransition temperature required to provide an air outlet temperature ofnot lower than 30° C. is about 50 to 60° C. or more as described above.

In the case of manufacturing the heat accumulator S2 of Embodiment 2 byvacuum brazing, as shown in FIG. 11, the outlet end plate 17 of the heataccumulator S2 is provided with a heat storage material encapsulationport 17 a for encapsulating the heat storage material, which isprotruded towards the outlet cover plate 18. In the outlet cover plate18, an encapsulation port hole 18 a penetrating the heat storagematerial encapsulation port 17 a is formed. The heat storage materialencapsulation port 17 a is closed by a cap 20 made of resin, rubber, orthe like after the heat storage material is encapsulated.

Each tank constituting element 19 includes first and second partitionwalls 19 a and 19 b, the third partition wall 19 c, the inner rib 19 d,and an outer rib 19 e arranged coaxially. The first and second partitionwalls 19 a and 19 b are radially joined at about four places of theentire circumference to form heat-insulating layer spaces 19 f betweenthe joint places. The second and third partition walls 19 b and 19 c areradially joined at about four places of the entire circumference to formheat storage layer spaces 19 g between the joint places. The spacesurrounded by the third partition wall 19 c serves as a liquid reservingportion space 19 h. The inner rib 19 d protrudes from the thirdpartition wall 19 c towards the liquid reserving portion 1. The outerrib 19 e protrudes outward from the first partition wall 19 a andincludes an axially bent portion at a part of the circumference forexterior shape alignment for stacking. At the joint places between thefirst and second partition walls 19 a and 19 b, positioning protrusions19 i protruding in a tank axis direction are formed (see FIG. 8).

In the heat accumulator S2 of Embodiment 2, a plurality of the tankconstituting elements 19 are stacked facing in alternate directions, andthe openings of the stacked tank constituting elements 19 at the bothends are closed by the inlet end and cover plates 15 and 16 and theoutlet end and cover plates 17 and 18 to constitute a container.

The liquid reserving portion 1 is composed of the liquid reservingportion spaces 19 h made to communicate with each other by stacking thetank constituting elements 19.

The vacuum heat-insulating layer 2 is formed by evacuating theheat-insulating layer spaces 19 f made to communicate with each other bystacking the tank constituting elements 19. The inlet end vacuumheat-insulating layer 3 is formed by evacuating the space formed by theinlet end and cover plates 15 and 16. The outlet end vacuumheat-insulating layer 4 is formed by evacuating the space formed by theinlet end and cover plates 17 and 18.

The heat storage layer 5 is composed of the heat storage layer spaces 19g made to communicate by stacking the tank constituting elements 19.

The heat insulator S2 of Embodiment 2 is manufactured by a manufacturingmethod as follows: Brazing filler metal is applied to the plurality oftank constituting elements 19, and the plurality of tank constitutingelements 19 are stacked. The openings of the stacked tank constitutingelements 19 at both ends are closed by the inlet and outlet cover plates16 and 18, temporarily assembling a container. The temporarily assembledcontainer is evacuated in a furnace and then the temperature isincreased for vacuum brazing, thus evacuating the vacuum heat-insulatinglayers 2, 3, and 4 and heat storage layer 5 together. Thereafter, theevacuated heat storage layer 5 is filled with the heat storage materialby vacuum suction.

Next, operations thereof are described.

[Manufacturing Method of Heat Accumulator]

FIG. 12 is a process diagram showing vacuum brazing of the heataccumulator S2 of Embodiment 2; FIG. 13 is a view showing an air grooveof the heat accumulator S2 of Embodiment 2, which is provided forincreasing the degree of vacuum at a brazing process in the furnace; andFIG. 14 is an explanatory view showing a heat storage materialencapsulation process at the vacuum brazing of the heat accumulator S2of Embodiment 2. Hereinafter, the vacuum brazing for the heataccumulator S2 of Embodiment 2 is described using FIGS. 12 to 14.

Tart Processing Process

In a first part processing process of step S1, the tank constitutingelements 19 are processed by pressing or punching plate materials.

In a second part processing process of step S2, the inlet and outletcover plates 16 and 18 are processed by pressing or punching platematerials.

In a third part processing process of step S3, the inlet and outlet endplates 15 and 17 are processed by pressing or punching plate materials.

In a fourth part processing process of step S4, the inlet and outletpipes 6 and 7 are processed by pipe forming of plate materials.

In a fifth part processing process of step S5, the cap 20 is formed bypressing or punching a plate material, drawing, or the like.

Brazing Filler Metal Applying Process

In a brazing filler metal applying process of step S6, brazing fillermetal is applied to the plurality of tank constituting elements 19 (forexample, stainless steel) processed at the first part processing processof the step S1.

Part Sub-Assembly Process (Stacking Process)

In a part sub-assembly process of step S7, a desired number of the tankconstituting elements 19 with the brazing filler metal applied theretoat the brazing filler metal applying process of the step S6 are stackedaccording to the designed value of the liquid storage capacity. In thecase of Embodiment 2, the plurality of tank constituting elements 19 arestacked facing in alternate directions so as to provide a stack shown inFIGS. 7 to 11.

Assembly Process

In an assembly process of step 8, the stacked tank constituting elements19 assembled in the part sub-assembly process of the step S7 are joinedwith the parts processed at the second to fifth part processingprocesses, including the inlet and outlet cover plates 16 and 18, theinlet and outlet end plates 15 and 17, the inlet and outlet pipes 6 and7, and the cap 20, to be temporarily built into a container shape as awhole. At this time, the brazing filler metal is applied to the portionsnecessary to be brazed other than the stacked constituting elements 19.

Jig Setting Process

In a jig setting process of step S9, the temporarily built-up containeris set to a brazing jig so that the individual parts temporarily builtinto the container shape in the assembly process of the step S8 are notdisplaced and secure the unity thereof.

Brazing Process

In a brazing process of the step S10, the individual parts are fixed byvacuum brazing at the following in-furnace process.

The in-furnace process includes: an evacuation process to evacuate theinside of the furnace (step S10 a); a warming process to increasetemperature within the furnace (step Slob); a brazing process to fix theparts with melted brazing filler metal (step S10 c); and a coolingprocess to cool the container fixed by brazing (step S10 d).

In the evacuation process of the step S10 a, in order to furtherincrease the degree of vacuum, as shown in FIG. 13( a), air grooves 19 jare formed at the joint places radially connecting the second and thirdpartition walls 19 b and 19 c. Accordingly, in the stacked tankconstituting elements 19, as shown in FIG. 13( b), the liquid reservingportion 1 and side vacuum heat-insulating layer 2 communicate with eachother through the pairs of air grooves 19 j and 19 j facing each other.

Air Sealing Process

In an air sealing process of step S11, the air tightness keeping thevacuum of the vacuum heat-insulating layers 2 to 4 and heat storagelayer 5 of the brazed container taken out of the furnace is secured.

Heat Storage Material Encapsulation Process

In a heat storage material encapsulation process of step S12, the heatstorage material is encapsulated using evacuation by the evacuated heatstorage layer 5.

Specifically, as shown in FIG. 14( a), in the case of vacuum brazing,the heat storage layer 5 is also evacuated. Moreover, in the heatstorage encapsulation port 17 a formed at the outlet end plate 17, athin wall portion 17 a′ made thinner than a standard plate thickness isformed.

As shown in FIG. 14( b), when the tip end of a filler charged with aheat storage material P (paraffin) is inserted into the heat storagematerial encapsulation port 17 a to break through the thin wall portion17 a′, the heat storage material P is sucked at once into the heatstorage layer 5 by vacuum suction force of the heat storage layer 5.Since the heat storage layer 5 is evacuated, the heat storage materialis uniformly encapsulated within a short time. After the heat storagelayer 5 is filled with the heat storage material P, the cap 20 isinserted and engaged as shown in FIG. 14( c) to close the broken heatstorage material encapsulation port 17 a.

Shipping Inspection Process

In a shipping inspection process of step S13, shipping inspection isperformed in terms of check items including whether the vacuum of thevacuum heat-insulating layer 2 is maintained with no brazing defects andwhether the heat storage layer 5 is filled with the heat storagematerial P.

Packing Process

In a packing process of step S14, products which pass the shippinginspection are packed.

Shipping Process

In a shipping process of step S15, the packed products are shipped froma factory.

[Heat Storing and Releasing Operation]

A description is given of heat storing and releasing operations by theheat accumulator 2 of Embodiment 2.

With regard to the heat absorbing operation of the heat storagematerial, while hot heat medium circulates through the liquid reservingportion 1 within the heat accumulator 2 by a flow from the inlet pipe 6to the outlet pipe 7, the heat storage material within the heat storagelayer 5 receives heat from the hot heat medium through the thirdpartition walls 19 c including the inner ribs 19 d. Upon receiving theheat, the heat storage material increases in temperature. When thetemperature of the heat storage material reaches the melting pointthereof, the heat storage material changes the phase thereof from thesolid to the liquid phase and absorbs heat energy along with this phasetransition.

In Embodiment 2, the heat storage material is paraffin capsules.Accordingly, when the temperature of the heat storage material is low asless than the melting point, the encapsulated paraffin is solid likewax. On the other hand, when the temperature of the heat storagematerial reaches the melting point or more, solid paraffin graduallyliquefies and becomes completely liquid within the capsules when theheat storage material absorbs heat at maximum.

With regard to the operation of storing heat in the heat medium withinthe liquid reserving portion 1, when a hot heat medium passing theliquid reserving portion 1 stops circulating, part of the hot heatmedium is enclosed in the liquid reserving portion 1 surrounded by twolayers of each of the vacuum heat-insulating layers 2 to 4 and heatstorage layer 5 and is prevented from decreasing in temperature. Theheat medium stored in the liquid reserving portion 1 within the heataccumulator S2 is kept hot.

In other words, even if the circulation of the hot medium is stopped fora long time and the outside temperature around the heat accumulator S2becomes low, the double heat-insulating structure by the vacuumheat-insulating layers 2 to 4 and heat storage layer 5 minimizes theheat energy escaping from the heat medium stored in the liquid reservingportion 1. It is therefore possible to achieve so high heat retention ofthe heat accumulator S2 that the heat medium of the liquid reservingportion 1 is kept hot even after a long period of time.

With regard to the operation of releasing the hot heat medium, in thecase of using the hot heat medium within the liquid reserving portion 1of the heat accumulator S2, first the hot heat medium of the liquidreserving portion 1 is released through the outlet pipe 7. Along withthe release of the hot heat medium, a cold heat medium is introducedinto the liquid reserving portion 1 of the heat accumulator 2 throughthe inlet pipe 6 and is mixed with the hot heat medium. Accordingly, thetemperature of the heat medium within the reservoir 1 of the heataccumulator S2 is lowered.

With regard to the operation of releasing heat from the heat storagematerial, when the heat medium within the liquid reserving portion 1 ofthe heat accumulator S2 decreases in temperature and draws heat from theheat storage material within the heat storage layer 5 through the thirdpartition walls 19 c including the inner ribs 19 d, the temperature ofthe heat storage material is lowered. When the temperature of the heatstorage material then reaches the freezing point, the phase of the heatstorage material changes from the liquid to the solid phase. Along withthis phase transition, the heat storage material releases the absorbedheat and continues to supply the heat energy due to the latent heat tothe heat medium through the third partition walls 19 c including theinner ribs 19 d, thus preventing the temperature of the heat medium frombeing lowered.

In Embodiment 2, the heat storage material is paraffin capsules.Accordingly, when the temperature of the heat storage material is higherthan the freezing point, the encapsulated paraffin is liquid. On theother hand, when the temperature of the heat storage material is reducedto the freezing point or less, liquid paraffin gradually solidifies torelease heat and becomes solid within the capsules when the heat storagematerial releases heat at maximum.

As described above, the heat accumulator 2 of Embodiment 2 effectivelyutilizes “sensible heat” stored in the heat medium with the heatretention maintained and “latent heat” released from the heat storagematerial of the heat storage layer 5.

Accordingly, in an application of the heat accumulator 2 to the enginecoolant circulation circuit, introducing hot engine coolant to theengine side at the start of the engine can considerably reduces timetaken for the engine to reach the engine warm-up temperature. Moreover,in another application thereof to the engine coolant circulationcircuit, introducing the hot engine coolant to the heater core side atthe start of the engine can increased the passenger compartment heatingperformance.

The “sensible heat” is heat energy stored without phase transition, and“latent heat” is heat energy absorbed or released during phasetransitions between the solid and liquid phases. The amount of heatstored in the form of “latent heat” is several orders of magnitudehigher than that of “sensible heat.”

[Heat Exchange Promotion Operation]

The heat accumulator S2 of Embodiment 2 includes the inlet end and coverplates 15 and 16, the outlet end and cover plates 17 and 18, and thetank constituting elements 19, and the inlet and outlet pipes 6 and 7are fixed to the inlet and outlet end plates 15 and 17, respectively. Onthe third partition walls 19 c separating the liquid reserving portionspaces 19 h of the tank constituting elements 19, the inner ribs 19 dprotruding in the direction orthogonal to the flow of the heat mediumfrom the inlet to the outlet are formed.

Accordingly, the flow of the heat medium from the inlet pipe 6 to theoutlet pipe 7 meanders along the protrusions and recesses composed ofthe third partition walls 19 c and inner ribs 19 d. When the heatstorage material encapsulated in the heat storage layer 5 absorbs heatfrom the heat medium, the effective area for heat absorption is largerthan that in the case of a straight cylindrical pipe, providing highheat absorption efficiency. In a similar way, when the heat storagematerial encapsulated in the heat storage layer 5 releases heat to theheat medium, the effective area for heat release is larger than that inthe case of the straight cylindrical pipe, thus resulting in high heatrelease efficiency. The protrusions and recesses composed of the thirdpartition walls 19 c and inner ribs 19 d can thus promote the heatexchange efficiency.

[Application Example of Heat Accumulator S2 to Engine CoolantCirculation System]

FIG. 15 is an engine coolant circulation circuit diagram showing a firstexample of an engine coolant circulation system including the heataccumulator S2 of Embodiment 2.

An engine 21 heating engine coolant while being driven and the engine 21and a heater core 22 which require the heated engine coolant when theengine is started from the engine stop state, where the temperature ofthe engine coolant decreases, are connected through an engine coolantcirculation circuit.

The engine coolant circulation circuit is provided with the heataccumulator S2 whose inlet side is connected to the engine 21 and whoseoutlet side is connected to the engine 21 and heater core 22.

The circuit connecting the engine 21 and the inlet side of the heataccumulator S2 is provided with a first valve 23, and the circuitconnecting the outlet side of the heat accumulator S2 and the engine 21and heater core 22 is provided with a second valve 24. The enginecoolant circulation circuit connecting the engine 21 and a radiator 25is provided with a thermo valve 26 and a circulation pump 27.

Operations of the first and second valves 23 and 24 and the circulationpump 27 are controlled by a controller 28.

The controller 28 makes control as follows: the controller 28 opens thefirst and second valves 23 and 24 while the engine 21 is being drivenand closes the first and second valves 23 and 24 when the engine 21 isstopped. At the start of the engine 21, the controller 28 opens thesecond valve 24 to the engine 21 side when the engine warm-up haspriority, and opens the second valve 24 to the heater core 22 side whenthe passenger compartment heating has priority.

Accordingly, at the start of the engine, by continuing to feed hotengine coolant from the heat accumulator S2 utilizing “sensible heat”and “latent heat,” expected promotion of warm-up of the engine 2 can beachieved when the engine warm-up has priority while an expected increasein heating performance in the passenger compartment can be achieved whenthe passenger compartment heating has priority.

FIG. 16 is an engine coolant circulation circuit diagram showing asecond example of the engine coolant circulation system including theheat accumulator S2 of Embodiment 2.

This second example is an example of further providing a pump 29 for thecircuit connecting the second valve 24 and the heater core 22 in theengine coolant circulation system shown in FIG. 15.

Accordingly, in addition to the effects of the first example, the secondexample further provides an effect on controlling the heatingperformance by regulating the flow rate when the passenger compartmentheating has priority.

[Application Example of Heat Accumulator S2 to Electrical Part CoolantCirculation System for Driving Motor]

FIG. 17 is a coolant circulation circuit diagram showing a first exampleof an electrical equipment coolant circulation system for a drivingmotor including the heat accumulator S2 of Embodiment 2.

In this first example, a vehicle-mounted heat source includes aninverter cooler 30 which heats inverter coolant while being driven and abattery cooler 31 which heats battery coolant while being driven. Avehicle-mounted heat demand source includes a heater core 22 of an airconditioner using the inverter coolant and battery coolant as heatingmedium.

The controller 28 makes control at the start of the engine to open thefirst valve 23 provided on the inlet side of the heat accumulator S1 andthe second valve 24 provided on the outlet side of the heat accumulatorS2. Accordingly, it is possible to achieve an expected increase inpassenger compartment heating performance at the start of the engine ina hybrid vehicle.

FIG. 18 is a coolant circulation circuit diagram showing a secondexample of the electrical equipment coolant circulation system for adriving motor including the heat accumulator S2 of Embodiment 2.

This second example is an example further providing the pump 29 for thecircuit connecting the second valve 24 and the heater core 22 in theelectrical equipment coolant circulation system for a driving motorshown FIG. 17.

Accordingly, in addition to the effects of the first example, the secondexample further provides an effect on controlling the heatingperformance by regulating the flow rate at the start of the engine.

Next, effects thereof are described.

In addition to the effect (1) in the heat accumulator S1 of Embodiment1, the heat accumulator S2 of Embodiment 2 can provide the effectsenumerated below.

(4) The heat storage layer 5 filled with the heat storage materialabsorbing and releasing heat during phase transition between liquid andsolid phases is provided between the liquid reserving portion 1 and eachof the vacuum heat-insulating layers 2, 3, and 4. Accordingly, it ispossible to provide the heat accumulator S2 having so high heat storageperformance that can increase the warm-up performance or passengercompartment heating performance at the start of the engine because of“latent heat” released from the heat storage material in the heatstorage layer 5.(5) The heat storage material is a paraffin material, as a latent heatstorage material, which stores the heat of fusion during phasetransition from the solid to the liquid phase in the temperature rangenot lower than the melting point and which releases the heat ofsolidification during phase transition from the liquid to the solidphase in the temperature range not higher than the freezing point.Accordingly, it is possible to obtain a high storage of heat even with alittle amount of the heat storage material. Moreover, the paraffinmaterial has high flexibility in setting the phase transitiontemperature, and accordingly, the phase transition temperature can beproperly set depending on the intended use.(6) The heat storage material includes paraffin capsules, which includethe paraffin material encapsulated in spherical coatings asmicrocapsules. The heat storage layer 5 is filled with aggregates of theparaffin capsules taking an account of a change in volume due to phasetransition between liquid and solid phases. Accordingly, the volatilecharacteristic, which is a fault of the paraffin material, can beprevented by the spherical coatings, and the operation of deformationforce due to the change in volume can be reduced, thus securing theendurance reliability for long-term use.(7) The heat accumulator S2 includes the inlet end and cover plates 15and 16, the outlet end and cover plates 17 and 18, and the tankconstituting elements 19 as the constituent parts. Moreover, the inletpipe 6 is fixed to the inlet end plate 15, and the outlet pipe 7 isfixed to the outlet end plate 17. Furthermore, on the third partitionwalls 19 c separating the liquid reserving portion spaces 19 h of thetank constituting elements 19, the inner ribs 19 d protruding in thedirection orthogonal to the flow of the heat medium from the inlet tooutlet is formed. Accordingly, the heat storage material encapsulated inthe heat storage layer 5 has high heat absorption and releaseefficiencies, thus accelerating the heat exchange. It is thereforepossible to provide a high latent heat effect by the heat storagematerial.(8) Each of the tank constituting elements 19 includes the first tothird partition walls 19 a to 19 c coaxially arranged. Theheat-insulating layer space 19 f is formed between the first and secondpartition walls 19 a and 19 b, and the heat storage layer space 19 g isformed between the second and third partition walls 19 b and 19 c. Theliquid reserving portion space 19 h is surrounded by the third partitionwall 19 c. The plurality of tank constituting elements 19 are stacked,and the openings of the stacked tank constituting elements 19 at theboth ends are closed by the inlet and outlet cover plates 16 and 18,thus constituting a container. The liquid reserving portion 1 iscomposed of the liquid reserving portion spaces 19 h made to communicatewith each other by stacking the tank constituting elements 19, and thevacuum heat-insulating layer 2 is composed of the heat-insulating layerspaces 19 f which are made to communicate by stacking the tankconstituting elements 19 and then evacuated. The heat storage layer 5 iscomposed of the heat storage layer spaces 19 g made to communicate bystacking the tank constituting elements 19. Accordingly, it is possibleto provide the stacking-type heat accumulator S2 which includes the heatstorage layer 5 and vacuum heat-insulating layer 2 at the outerperiphery of the liquid reserving portion 1 and has a high heat storageperformance and high responsiveness to the request to change thenecessary capacity.(9) The heat accumulator S2 is manufactured as follows: The plurality oftank constituting elements 19 are stacked on each other with the brazingfiller metal applied thereto, and the openings of the stacked tankconstituting elements 19 at the both ends are closed with the inlet andoutlet cover plates 16 and 18, thus temporarily assembling a container.Vacuum brazing is then performed to evacuate the temporarily assembledcontainer within the furnace and then to increase the temperaturethereof to evacuate both the heat-insulating layer 2 and heat storagelayer 5. The evacuated heat storage layer 5 is filled with the heatstorage material P by vacuum suction. In other words, fixing of theparts and evacuation are both performed at the vacuum brazing process.Accordingly, compared to the case where the parts are fixed by welding,brazing, or the like and then the vacuum heat-insulating layer isevacuated by a different process, it is possible to reduce variations inthe degree of vacuum of the vacuum heat-insulating layer 2 and shortenthe manufacturing time because of the simplified process. Moreover, byusing the vacuum of the heat storage layer 5, the heat storage materialP can be encapsulated by vacuum suction. Accordingly, the heat storagelayer 5 can be uniformly filled with the heat storage material P withina short encapsulation time.

The method of manufacturing the heat accumulator 2 of Embodiment 2 canprovide the effects enumerated below in addition to the effect (1) ofthe method of manufacturing the heat accumulator S1 of Embodiment 1.

(4) The heat accumulator S2 includes the heat storage layer 5 and vacuumheat-insulating layer 2 at the outer periphery of the liquid reservingportion 1, and the heat storage layer 5 is filled with the heat storagematerial P which absorbs and releases heat along with its phasetransition between liquid and solid phases. The part processingprocesses (steps S1 to S5) processes the inlet and outlet cover plates16 and 18 and the tank constituting elements 19 each of which includesthe liquid reserving portion space 19 h, heat storage layer space 19 g,and heat-insulating layer space 19 f and which is a plate material witha same cross-sectional shape, and the temporary assembly process (stepsS6 to S8) stacks the plurality of tank constituting elements 19 andcloses the openings thereof with the inlet and outlet cover plates 16and 18, thus forming the liquid reserving portion 1, heat storage layer5, and vacuum heat-insulating layer 2. Accordingly, it is possible toprovide the method of manufacturing the stacking-type heat accumulatorS2 which including the heat storage layer 5 and vacuum heat-insulatinglayer 2 at the outer periphery of the liquid reserving portion 1 and hasa high heat storage performance and high responsiveness to the requestto change the necessary capacity.(5) In the joint surfaces of the stacked tank constituting elements 19,the air grooves 19 j are provided at the joint places connecting theliquid reserving portion space 19 h and heat-insulating layer space 19 fwith the heat storage space 19 g interposed therebetween. In the brazingprocess (step 10), the liquid reserving portion spaces 19 h and theheat-insulating layer spaces 19 f communicate with each other throughthe air grooves 19 j at evacuation within the furnace, and the airgrooves 19 j are filled and closed with the brazing filler metal bycapillary at brazing by increasing the temperature within the furnace.Accordingly, air is smoothly evacuated from the heat-insulating layerspaces 19 f by evacuation at the brazing process, thus furtherincreasing the degree of vacuum of the vacuum heat-insulating layer 2.(6) The brazing process (step S10) evacuates the heat storage layer 5together with the vacuum heat-insulating layer 2 to less than theatmospheric pressure at the end of the process. After the brazingprocess, the heat storage material encapsulation process (step S12) isadded, which fills the evacuated heat storage layer 5 with the heatstorage material P by vacuum suction and then seals the encapsulationport. Accordingly, at encapsulating the heat storage material P in theheat storage layer 5 using the evacuated heat storage layer 5, the heatstorage material P can be encapsulated uniformly and within a shortertime compared to the case of encapsulating the heat storage material Pby pouring in the air atmosphere.(7) The heat storage material encapsulation port 17 a formed in theoutlet end plate 17 includes the thin wall portion 17 a′ made thinnerthan the standard plate thickness. In the heat storage materialencapsulation process (step S12), the tip of the injector charged withthe heat storage material P is inserted into the heat storage materialencapsulation port 17 a to break through the thin wall portion 17 a,thus the heat storage layer 5 is caused to suck the heat storagematerial P thereinto by vacuum suction. After the heat storage layer 5is filled with the heat storage material P, the cap 20 is inserted intoand engaged with the broken heat storage material encapsulation port 17a to close the port 17 a. Accordingly, in encapsulating the heat storagematerial P in the heat storage layer 5 using the evacuated heat storagelayer 5, by using the heat storage material encapsulation port 17 aincluding the previously formed thin wall portion 17 a′, the heatstorage material P can be encapsulated in the heat storage layer 5 withan easy insert operation. Moreover, the encapsulation port can be sealedwith the easy operation of inserting the cap 20.

Embodiment 3

Embodiment 3 is an example of a method of manufacturing amulti-container type heat accumulator including a liquid reservingportion, a heat-insulting layer, and a heat storage layer whileEmbodiment 2 shows the method of manufacturing the stacking-type heataccumulator.

First, the constitution thereof is described.

FIG. 19 is a vertical-sectional front view showing a heat accumulatormanufactured by a manufacturing method of Embodiment 3. FIG. 20 is anenlarged view of part C of FIG. 19 showing the heat accumulatormanufactured by the manufacturing method of Embodiment 3. FIG. 21 is anexternal perspective view showing the heat accumulator manufactured bythe manufacturing method of Embodiment 3. FIG. 22 is a sectionalperspective view showing the heat accumulator manufactured by themanufacturing method of Embodiment 3. FIG. 23 is an exploded perspectiveview showing the heat accumulator manufactured by the manufacturingmethod of Embodiment 3.

As shown in FIGS. 19 to 23, the heat accumulator S3 of Embodiment 3includes a liquid reserving portion 1, a side vacuum heat-insulatinglayer (vacuum heat-insulating layer) 2, an inlet end vacuumheat-insulating layer 3 (vacuum heat-insulating layer), an outlet endvacuum heat-insulating layer 4 (heat-insulating layer), a heat storagelayer 5, an inlet pipe 6, an outlet pipe 7, a first cylinder side plate38 (a cylindrical member), a first inlet end plate 39 (an inlet platemember), a first outlet end plate 40 (an outlet plate member), a secondcylinder side plate 41 (a cylindrical member), a second inlet end plate42 (an inlet plate member), a second outlet end plate 43 (an outletplate member), and an accordion cylinder plate 44 (a cylindricalmember).

The heat accumulator S3 of Embodiment 3 includes the vacuumheat-insulating layers 2, 3, and 4 at the outer periphery of the liquidreserving portion 1 and a heat storage layer 5 between the liquidreserving portion 1 and the side vacuum heat-insulating layer 2, theheat storage layer 5 being filled with a heat storage material whichabsorbs and releases heat along with its phase transition between liquidand solid phases.

The liquid reserving portion 1 is provided with the inlet pipe 6 throughwhich a heat medium flows into the liquid reserving portion 1 and theoutlet pipe 7 through which the heat medium flows out. The wall memberseparating the liquid reserving portion 1 and the heat storage layer 5is the accordion cylinder plate 44 having roughness of a waveformsectional shape in a direction orthogonal to the flow of the heat mediumfrom the inlet to the outlet.

The inlet pipe 6 penetrates the second and first inlet end plates 42 and39 to be fixed, and the outlet pipe 7 penetrates the second and firstoutlet end plates 43 and 40 to be fixed.

The heat storage material filled in the heat storage layer 5 is aparaffin material as a latent heat storage material. The paraffinmaterial stores heat of fusion during phase transition from the solid tothe liquid phase in a temperature range not lower than the meltingtemperature and releases heat of solidification during phase transitionfrom the solid phase to the liquid phase in a temperature range nothigher than the freezing temperature. The heat storage material includesparaffin capsules, which include the paraffin material encapsulated inspherical coatings as microcapsules. The heat storage layer 5 is filledwith aggregates of the paraffin capsules taking an account of a changein volume (about 10%) along with its phase transition between the liquidand solid phases.

The inner container includes the first cylinder side plate 38, firstinlet end plate 39, and first outlet end plat 40. Within the firstcylinder side plate 38, the accordion cylinder plate 44 is providedcoaxially with the first cylinder side plate 38.

The outer container is provided outside of the inner container andincludes the second cylinder side plate 41, second inlet end plate 42,and second outlet end plate 43.

The liquid reserving portion 1 is composed of a cylindrical spacesurrounded by the accordion cylinder plate 44, first inlet end plate 39,and first outlet end plate 40. Positioning of the accordion cylinderplate 44 relative to the both end plates 39 and 40 is performed by astep 39 a formed in the first inlet end plate 39 and a step 40 a formedin the first outlet end plate 40.

The heat-insulating layer includes the side vacuum heat-insulating layer2, inlet end vacuum heat-insulating layer 3, and outlet end vacuumheat-insulating layer 4 and is composed of evacuated gap formed betweenthe inner and outer containers.

The side vacuum heat-insulating layer 2 is formed as a cylindrical layerbetween the first and second cylinder side plates 38 and 41. The inletend vacuum heat-insulating layer 3 is formed between the first andsecond inlet end plates 39 and 42. The outlet end vacuum heat-insulatinglayer 4 is formed between the first and second outlet end plates 40 and43. The radial gap of the side vacuum heat-insulating layer 2 ispositioned by an annular protrusion 42 a formed in the second inlet sideplate 42 and an annular protrusion 43 a formed in the second outlet endplate 43 and can be maintained at constant without changing the relativeposition even if external force is applied thereto.

The heat storage layer 5 is composed of a cylindrical space formedbetween the first cylinder side plate 38 and accordion cylinder plate44. The radial gap of the heat storage layer 5 can be maintained atconstant by the first cylinder plate 38 positioned by the annularprotrusions 42 a and 43 a and the accordion cylinder plate 44 positionedby the steps 39 a and 40 a.

Next, the operations thereof are described.

[Heat Storage Operation]

With regard to the heat absorbing operation of the heat storagematerial, while a hot heat medium circulates through the liquidreserving portion 1 within the heat accumulator S3 through a flow fromthe inlet pipe 6 to the outlet pipe, the heat storage material withinthe heat storage layer 5 receives heat from the hot heat medium throughthe accordion cylinder plate 44. Upon receiving the heat, the heatstorage layer increases in temperature. When the temperature of the heatstorage material reaches the melting point of the heat storage material,the heat storage material changes the phase thereof from the solid tothe liquid phase and absorbs heat energy during this phase transition.

In Embodiment 3, the heat storage material includes paraffin capsules.Accordingly, when the temperature of the heat storage material is as lowas less than the melting point, the encapsulated paraffin is solid likewax. On the other hand, when the temperature of the heat storagematerial reaches the melting point or more, solid paraffin graduallyliquefies and becomes completely liquid within the capsules when theheat storage material absorbs heat at maximum.

With regard to the operation of storing heat in the heat medium withinthe liquid reserving portion 1, when the hot heat medium passing theliquid reserving portion 1 stops circulating, as shown in FIG. 24( a),part of the hot heat medium is enclosed in the liquid reserving portion1 surrounded by two layers of each of the vacuum heat-insulating layers2 to 4 and the heat storage layer 5 and is prevented from cooling. Theheat medium stored in the liquid reserving portion 1 is kept hot.

In other words, even if the circulation of the hot medium is stopped fora long time and the outside temperature around the heat accumulator S3becomes low, the double heat-insulating structure of each of the vacuumheat-insulating layers 2 to 4 and the heat storage layer 5 minimizes theheat energy escaping from the heat medium stored in the liquid reservingportion 1. It is therefore possible to achieve so high heat retentionthat the heat medium of the liquid reserving portion 1 is kept hot evenafter a long period of time.

[Heat Releasing Operation]

With regard to the operation of releasing the hot heat medium, in thecase of using the hot heat medium within the liquid reserving portion 1of the heat accumulator S3, first the hot heat medium of the liquidreserving portion 1 is released through the outlet pipe 7. Along withthe release of the hot heat medium, as shown in FIG. 24( b), cold heatmedium is introduced into the liquid reserving portion 1 of the heataccumulator S3 through the inlet pipe 6 and mixed with the hot heatmedia, lowering the temperature of the heat medium within the reservoir1 of the heat accumulator S3.

With regard to the operation of releasing heat from the heat storagematerial, when the heat medium within the liquid reserving portion 1 ofthe heat accumulator S3 becomes cold and draws heat from the heatstorage material within the heat storage layer 5 through the accordioncylinder plate 44, the temperature of the heat storage material islowered. When the temperature of the heat storage material then reachesthe freezing point, the phase of the heat storage material changes fromthe liquid to the solid phase as shown in FIG. 24( c). During the phasetransition, the heat absorbed by the heat storage material is released,and the heat energy by the latent heat continues to be supplied to theheat medium through the accordion cylinder plate 44, thus preventing thetemperature of the heat medium from being lowered.

In Embodiment 3, the heat storage material includes the paraffincapsules. Accordingly, when the temperature of the heat storage materialis higher than the freezing point, the encapsulated paraffin is liquid.On the other hand, when the temperature of the heat storage material isreduced to the freezing point or less, liquid paraffin graduallysolidifies to release heat and becomes solid within the capsules whenthe heat storage material releases heat at maximum.

[Heat Storage Performance Comparison]

Comparison is made for the heat storage performance based on thecomparative characteristics of the engine coolant temperature at thestart of the engine shown in FIG. 25.

In FIG. 25, the characteristic indicated by a dotted line shows anengine coolant temperature characteristic in the case where there is noheat accumulator in the circulation circuit of engine coolant; thecharacteristic indicated by a dashed-dotted line shows an engine coolanttemperature characteristic in the case where a conventional heataccumulator is provided in the circulation circuit of engine coolant;and the characteristic indicated by a solid line shows an engine coolanttemperature characteristic in the case where the heat accumulator S3 isprovided in the circulation circuit of engine coolant.

When the engine starts in the case where there is no heat accumulator inthe circulation circuit of engine coolant, as indicated by the dottedline of FIG. 25, the engine coolant temperature which is equal to theoutside temperature level at the start of the engine increases by theheat energy due to the engine being driven. In FIG. 25, it is assumedthat the engine coolant temperature increases at a constant gradient.

When the engine starts in the case where the conventional heataccumulator (including only the vacuum heat-insulating layer) isprovided in the circulation circuit of engine coolant, as indicated bythe dashed-dotted line of FIG. 25, hot engine coolant is fed from theheat accumulator at the start of the engine, and accordingly the enginecoolant temperature rises just after the start. However, the hot enginecoolant is immediately mixed with cold engine coolant to drop intemperature. The engine coolant temperature then increases along thedotted line.

When the engine starts in the case where the heat accumulator S3 ofEmbodiment 3 is provided in the circulation circuit of engine coolant,as indicated by the solid line of FIG. 25, hot engine coolant is fedfrom the heat accumulator at the start of the engine, and the enginecoolant temperature rises just after the start. Subsequently, the hotengine coolant is mixed with cold engine coolant to once drop intemperature. However, release of the heat stored in the heat storagematerial prevents the drop in temperature of the engine coolant, and theengine coolant temperature increases during and after the second cycle.

The comparison in performances of the heat accumulators by the coolanttemperature characteristics relates to “sensible heat” and “latentheat.” The “sensible heat” is heat energy stored without phasetransition. The “latent heat” is heat energy absorbed or released alongwith its phase transitions between solid and liquid phases. The amountof heat stored in the form of “latent heat” is several orders ofmagnitude higher than that of “sensible heat.”

On the other hand, a conventional heat accumulator (for example, seeJapanese Patent Application publication No. 2004-20027) stores hotengine coolant, or utilizes only the “sensible heat.” As shown in FIG.25, therefore, once the stored hot engine coolant is used out, there isno addition of heat energy. In other words, the sensible heat effect islow. Accordingly, compared to time T3 for the engine coolant to reachwarm-up temperature in the case where there is no heat accumulator inthe engine coolant circulation circuit, time T2 for the engine coolantto reach the warm-up temperature is just slightly shortened.

On the other hand, the heat accumulator S3 of Embodiment 3 holdstemperature retention while utilizing both the sensible heat stored inthe heat medium and the latent heat released from the heat storagematerial of the heat storage layer 5. As shown in FIG. 25, therefore, tothe sensible heat effect, the latent heat effect providing additionalheat energy is added. Accordingly, compared to the time T3 for theengine coolant to reach the warm-up temperature in the case where thereis no heat accumulator in the engine coolant circulation circuit, timeT1 for the engine coolant to reach the warm-up temperature isconsiderably shortened.

[Heat Accumulator Manufacturing Method]

The heat accumulator S3 of Embodiment 3 is manufactured by vacuumbrazing including a part processing process, a temporary assemblyprocess, and a brazing process.

Part Processing Process

In the part processing process, the constituent parts constituting theheat accumulator S3 are processed. Specifically, the three cylindricalmembers 38, 41, and 44 forming the liquid reserving portion 1, heatstorage layer 5, and vacuum heat-insulating layer 2, the inlet platemembers 39 and 42, the outlet plate members 40 and 43, and the inlet andoutlet pipes 6 and 7 are processed by pressing, punching, or the like.

Temporary Assembly Process

In the temporary assembly process, the processed constituent parts areassembled into a container. Specifically, the three cylindrical members38, 41, and 44 are assembled in a coaxial form, and the openings thereofare covered with the inlet plate members 39 and 42 and the outlet platemembers 40 and 43, thus forming the liquid reserving portion 1, heatstorage layer 5, and vacuum heat-insulating layer 2.

Brazing Process

In the brazing process, after brazing filer metal is applied to theassembled parts and the assembled parts are shaped into a container by ajig, the assembled container is put into a furnace and subjected to: aevacuation process of evacuating the inside of the furnace; a warmingprocess of increasing the temperature within the furnace; a brazingprocess of fixing the parts with the melted brazing filler metal; and acooling process of cooling the container fixed by brazing, thuscompleting fixation by brazing.

As for the encapsulation of the heat storage material in the heatstorage layer 5, similar to the case of Embodiment 2, the heat storagelayer 5 may be filled by evacuation, or the heat storage material may bepoured into the heat storage layer 5 in the air atmosphere.

Through the aforementioned processes, the heat accumulator S3 ismanufactured.

In the brazing process, therefore, by controlling the vacuum atmospherein the furnace into a stable vacuum atmosphere, compared to the case ofevacuation in the air atmosphere under individual control, the vacuumheat-insulating layers 2, 3, and 4 having stable and unvarying vacuumquality can be formed.

Moreover, in the brazing process, fixation of the parts and evacuationcan be both achieved. Accordingly, compared to the case of evacuatingthe vacuum heat-insulating layers in another process after fixing theparts by welding or the like, the processes can be simplified, and themanufacturing efforts and time can be reduced.

Next, the effects thereof are described.

The method of manufacturing the heat accumulator S3 of Embodiment 3 canprovide the following effects in addition to the effect of (1) of themethod of manufacturing the heat accumulator S1 of Embodiment 1:

(8) The heat accumulator S2 includes the heat storage layer 5 and vacuumheat-insulating layer 2 at the outer periphery of the liquid reservingportion 1, and the heat storage layer 5 is filled with the heat storagematerial P which absorbs and releases heat along with its phasetransition between liquid and solid phases. In the part processingprocess, the three cylindrical members 38, 41, and 44 forming the liquidreserving portion 1, heat storage layer 5, and vacuum heat-insulatinglayer 2, the inlet plate members 39 and 42, and the outlet end platemembers 40 and 43 are processed. In the temporary assembly process, thethree cylindrical members 38, 41, and 44 are assembled in a coaxialfashion, and the openings thereof are covered with the inlet platemembers 39 and 42 and the outlet plate members 40 and 43, thus formingthe liquid reserving portion 1, heat storage layer 5, and vacuumheat-insulating layer 2. It is therefore possible to provide the methodof manufacturing the multi-container type heat accumulator S3 whichincludes the heat storage layer 5 and vacuum heat-insulating layer 2 atthe outer periphery of the liquid reserving portion 1 and having a highheat storage performance.

Embodiment 4

Embodiment 4 is an example of an application of the heat accumulator S2of Embodiment 2 or the heat accumulator S3 of Embodiment 3 (hereinafter,referred to as a heat accumulator 5) to a vehicle-mounted thermal systemin which a vehicle-mounted heat source and a vehicle-mounted heat demandsource are connected through a heat medium circuit.

First, the constitution thereof is described.

FIG. 26 is an engine coolant circulation circuit diagram showing anengine coolant circulation system (an example of a vehicle-mountedthermal system) including the heat accumulator S of Embodiment 4.

The engine 21 (the vehicle-mounted heat source) which heats enginecoolant (heat medium) while being driven and the engine 21 and heatercore 22 (the vehicle-mounted heat demand source) which demands heatedengine coolant at the start of the engine from the engine stopped statewhere the temperature of the engine coolant decreases are connectedthrough the engine coolant circulation circuit.

The engine 21 serves as the vehicle-mounted heat source because theengine 21 heats the coolant while being driven and also serves as thevehicle-mounted heat demand source because the temperature of thecoolant drops while the engine 21 is stopped.

The heater core 22, which is arranged in a unit of an air conditionercontrolling temperature in the passenger compartment, uses the enginecoolant as the heating medium and therefore serves as thevehicle-mounted heat demand source.

In the engine coolant circulation circuit, the heat accumulator S whoseinlet is connected to the engine 21 and whose outlet is connected to theengine 21 and heater core 22 is provided.

In the heat accumulator S, the heat storage layer 5 filled with the heatstorage material which absorbs or releases heat during the phasetransition between liquid and solid phases is provided between theliquid reserving portion 1 and each of the heat-insulating layers 2, 3,and 4 (see Embodiments 2 and 3).

The circuit connecting the engine 21 and the inlet of the heataccumulator S is provided with a first valve 23, and the circuitconnecting the outlet of the heat accumulator S and the engine 21 andheater core 22 is provided with a second valve 24. The engine coolantcirculation circuit connecting the engine 21 and radiator 25 is providedwith a thermo-valve 26 and a circulation pump 27.

The operations of the first and second valves 23 and 24 and circulationpump 27 are controlled by a controller 28 (a heat medium circulationcontrolling unit).

The controller 28, basically, makes control to open the first and secondvalve 23 and 24 while the engine is being driven; closes the first andsecond valves 23 and 24 when the engine 21 stops; and open the first andsecond valves 23 and 24 when the engine 21 starts.

On the other hand, in the case of Embodiment 4, there are twovehicle-mounted demand sources. The controller 28 therefore makescontrol to open the second valve 24 to the engine 21 at the start of theengine when the engine warm-up has priority and open the second valve 24to the heater core 22 at the start of the engine while the passengercompartment heating has priority.

Next, the operations thereof are described.

[Heat Storing Operation]

During normal running state by engine drive, by the controller 28, thefirst valve 23 is opened; and during use of a heater, the second valve24 is opened to the heater core 22; and the circulation pump 27 isdriven.

Accordingly, as shown in FIG. 27( a), hot engine coolant from the engine21 passes the heat accumulator S from the inlet to the outlet and isfurther fed to the engine 21 through the heater core 22 during use ofthe heater. When the temperature of the engine coolant increases andreaches the melting point of the heat storage material, the heat storagematerial changes the phase thereof from the solid to the liquid phaseand absorbs heat energy during this phase transition.

When the engine 21 stops, by the controller 28, the first and secondvalves 23 and 24 are closed, and the circulation pump 27 is stopped.

Accordingly, as shown in FIG. 27( b), the engine coolant is enclosed inthe liquid reserving portion 1 surrounded by the two layers of each ofthe heat-insulating layers 2, 3, and 4 and the heat storage layer 5. Theengine coolant stored in the heat accumulator S is therefore preventedfrom decreasing in temperature and is kept hot.

[Engine Warm-Up Priority]

Thereafter, when the engine warm-up has priority, at the start of theengine 21, by the controller 28, the first valve 23 is opened; thesecond valve 24 is opened to the engine 21; and the circulation pump isdriven.

Accordingly, as shown in FIG. 27( c), the hot engine coolant stored inthe heat accumulator S is fed to the engine 21 during the first cycle ofthe circulation cycles of the engine coolant. The hot engine coolant isaffected by the temperature of the system environment and is mixed withcold engine coolant. The temperature of the engine coolant within theheat accumulator S therefore decreases.

However, during and after the second cycle where the temperature of theheat storage material decreases to the freezing point because of thedecrease in temperature of the engine coolant within the heataccumulator S, the heat storage material changes the phase thereof fromthe liquid to the solid phase. The heat stored in the heat storagematerial is released during this phase transition, and the heat energydue, to the latent heat continues to be supplied to the engine coolant.During and after the second cycle, the decrease in temperature of theengine coolant is prevented by the heat released from the heat storagematerial, and the engine coolant kept hot is fed to the engine 21.

[Passenger Compartment Heating Priority]

On the other hand, when the passenger compartment heating has priority,at the start of the engine 21, by the controller 28, the first valve 23is opened; the second valve 24 is opened to the heater core 22; and thecirculation pump 27 is driven.

Accordingly, as shown in FIG. 27( d), the hot engine coolant stored inthe heat accumulator S is fed to the heater core 22 during the firstcycle of the circulation cycles of the engine coolant. The hot enginecoolant is affected by the temperature of the system environment and ismixed with cold engine coolant. The temperature of the engine coolantwithin the heat accumulator S therefore decreases.

However, during and after the second cycle where the temperature of theheat storage material decreases to the freezing point because of thedecrease in temperature of the engine coolant within the heataccumulator S, the heat storage material changes the phase thereof fromthe liquid to the solid phase. The heat stored in the heat storagematerial is released during this phase transition, and the heat energydue to the latent heat continues to be supplied to the engine coolant.During and after the second cycle, the decrease in temperature of theengine coolant is prevented by the heat released from the heat storagematerial, and the engine coolant kept hot is fed to the heater core 22.

Next, the effects thereof are described.

The engine coolant circulation system including the heat accumulator Sof Embodiment 4 can provide the effects enumerated below:

(1) In the vehicle-mounted thermal system in which the vehicle-mountedheat source which heats the heat medium while the power unit is beingdriven is connected, through the heat medium circuit, to thevehicle-mounted heat demand source which requires the hot heat mediumwhen the power unit starts from the power unit stopped state where thetemperature of the heat medium decreases, the heat medium circuit isprovided with the heat accumulator S whose inlet is connected to thevehicle-mounted heat source and whose outlet is connected to thevehicle-mounted heat demand source. The heat accumulator S includes theheat storage layer 5 between the liquid reserving portion 1 and each ofthe heat-insulating layer 2, 3, and 4, the heat storage layer 5 beingfilled with the heat storage material absorbing or releasing heat alongwith its phase transition between liquid and solid phases. The circuitconnecting the vehicle-mounted heat source and the inlet of the heataccumulator S is provided with the first valve 23, and the circuitconnecting the outlet of the heat accumulator S and the vehicle-mountedheat demand source is provided with the second valve 24. Furthermore,the vehicle-mounted thermal system includes the controller 28 whichopens the first and second valves 23 and 24 while a power unit is beingdriven; closes the same when the power unit stops; and opens the samewhen the power unit starts. Accordingly, with such a simple heat mediumcirculation control, the hot heat medium continues to be fed to thevehicle-mounted heat demand source from the heat accumulator S utilizing“sensible heat” and “latent heat” at the start of the power unit. It istherefore possible to achieve expected engine warm-up promotion and anexpected increase in passenger compartment heating performance.(2) The vehicle-mounted heat source includes the engine 21 heating thecoolant while being driven, and the vehicle-mounted heat demand sourceincludes the engine 21 which decreases the temperature of the coolantwhile being stopped and the heater core 22 of the air conditioner usingthe engine coolant as the heating medium. The controller 28 opens thesecond valve 24 to the engine 21 at the start of the engine when theengine warm-up has priority and opens the second valve 24 to the heatercore 22 at the start of the engine when the passenger compartmentheating has priority. Accordingly, with such a simple heat mediumcirculation control, it is possible to achieve expected warm-uppromotion of the engine 21 when the engine warm-up has priority and toachieve an expected increase in passenger compartment heatingperformance when the passenger compartment heating has priority.

Embodiment 5

Embodiment 5 is an example of, in the engine coolant circulation systemincluding the heat accumulator S of Embodiment 4, further including apump 29 in the circuit connecting the second valve 24 and heater core22.

First, the constitution thereof is described.

FIG. 28 is an engine coolant circulation circuit diagram showing anengine coolant circulation system (an example of the vehicle-mountedthermal system) including the heat accumulator S of Embodiment 5.

In Embodiment 5, the vehicle-mounted heat source includes the engine 21which heats the coolant while being driven, and the vehicle-mounted heatdemand source includes the engine 21 which decreases the temperature ofthe coolant while being stopped and the heater core 22 of an airconditioner using the engine coolant as the heating medium.

The circuit connecting the second valve 24 and heater core 22 isprovided with the pump 29. The controller 28 opens the valve 24 to theengine 21 at the start of the engine 21 when the engine warm-up haspriority. When the passenger compartment heating has priority, at thestart of the engine 21, the controller 28 opens the second valve 24 tothe heater core 22 and activates the pump 29 to regulate the rate offlow from the heat accumulator S to the heater core 22. For the otherconstitution is the same as that of Embodiment 4, correspondingcomponents are given the same reference numerals and symbols, and thedescription thereof is omitted.

Next, the operations thereof are described.

[Heat Storing Operation].

During normal running state by engine drive, by the controller 28, thefirst valve 23 is opened, and during use of a heater, the second valve24 is opened to the heater core 22, and the pump 29 and circulation pump27 are driven.

Accordingly, as shown in FIG. 29( a), hot engine coolant from the engine21 passes the heat accumulator S from the inlet to the outlet and,during use of the heater, is further fed to the engine 21 through theheater core 22. When the temperature of the engine coolant increases andreaches the melting point of the heat storage material, the heat storagematerial changes the phase thereof from the solid to the liquid phaseand absorbs heat energy during this phase transition.

When the engine 21 then stops, by the controller 28, the first andsecond valves 23 and 24 are closed, and the pump 29 and circulation pump27 are stopped.

Accordingly, as shown in FIG. 29( b), the engine coolant is enclosed inthe liquid reserving portion 1 surrounded by the two layers of each ofthe heat-insulating layers 2, 3, and 4 and the heat storage layer 5. Thedecrease in temperature of the engine coolant stored in the heataccumulator S is therefore prevented, and the engine coolant is kepthot.

[Engine Warm-up Priority]

Thereafter, when the engine warm-up has priority, at the start of theengine 21, by the controller 28, the first valve 23 is opened; thesecond valve 24 is opened to the engine 21; and the circulation pump 27is driven.

Accordingly, as shown in FIG. 29( c), the hot engine coolant stored inthe heat accumulator S is fed to the engine 21 during the first cycle ofthe circulation cycles of the engine coolant. The hot engine coolant isaffected by the temperature of the system environment and is mixed withcold engine coolant. The temperature of the engine coolant within theheat accumulator S therefore decreases.

However, during and after the second cycle where the temperature of theheat storage material decreases to the freezing point because of thedecrease in temperature of the engine coolant within the heataccumulator S, the heat storage material changes the phase thereof fromthe liquid to the solid phase. The heat stored in the heat storagematerial is released during this phase transition, and the heat energydue to the latent heat continues to be supplied to the engine coolant.During and after the second cycle, the decrease in temperature of theengine coolant is prevented by the heat released from the heat storagematerial, and the engine coolant kept hot is fed to the engine 21.

[Passenger Compartment Heating Priority]

On the other hand, when the passenger compartment heating has priority,at the start of the engine 21, by the controller 28, the first valve 23is opened; the second valve 24 is opened to the heater core 22 while thepump 29 is driven and controlled; and the circulation pump 27 is driven.

Accordingly, as shown in FIG. 29( d), the hot engine coolant stored inthe heat accumulator S is fed to the heater core 22 during the firstcycle of the circulation cycles of the engine coolant. The hot enginecoolant is affected by the temperature of the system environment and ismixed with cold engine coolant. The temperature of the engine coolantwithin the heat accumulator S therefore decreases.

However, during and after the second cycle where the temperature of theheat storage material decreases to the freezing point because of thedecrease in temperature of the engine coolant within the heataccumulator S, the heat storage material changes the phase thereof fromthe liquid to the solid phase. The heat stored in the heat storagematerial is released during this phase transition, and the heat energydue to the latent heat continues to be supplied to the engine coolant.During and after the second cycle, the decrease in temperature of theengine coolant is prevented by the heat released from the heat storagematerial, and the engine coolant kept hot is fed to the heater core 22through the pump 29 regulating the flow rate.

Next, the effects thereof are described.

The engine coolant circulation system including the heat accumulator Sof Embodiment 5 can provide the effects enumerated below in addition tothe effect (1) of Embodiment 4:

(3) The vehicle-mounted heat source includes the engine 21 which heatsthe coolant while being driven, and the vehicle-mounted heat demandsource includes the engine 21 which decreases the temperature of thecoolant while being stopped and the heater core 22 of an air conditionerusing the engine coolant as the heating medium. The circuit connectingthe second valve 24 and the heater core 22 is provided with the pump 29.Furthermore, the controller 28 opens the second valve 24 to the engine21 at the start of the engine 21 when the engine warm-up has priorityand opens the second valve 24 to the heater core 22 and activates thepump 29 to regulate the rate of flow from the heat accumulate S to theheater core 22 at the start of the engine 21 when the passengercompartment heating has priority. Accordingly, with such a simple heatmedium circulation control, when the engine warm-up has priority, it ispossible to achieve expected engine warm-up promotion. Furthermore, whenthe passenger compartment heating has priority, it is possible toachieve an expected increase in passenger compartment heatingperformance and control the heating performance by regulating the flowrate.

Embodiment 6

Embodiment 6 is an example of an application of an electrical equipmentcoolant circulation system for a drive motor of a hybrid vehicle whileEmbodiments 4 and 5 are application examples of the engine coolantcirculation system of an engine vehicle.

First, the constitution thereof is described.

FIG. 30 is a coolant circulation circuit diagram showing an electricalequipment coolant circulation system for a drive motor (an example ofthe vehicle-mounted thermal system) including the heat accumulator S ofEmbodiment 6.

In Embodiment 6, the vehicle-mounted source includes an inverter cooler30 which heats inverter coolant while being driven and a battery cooler31 which heats battery coolant while being driven. The vehicle-mountedheat demand source includes the heater core 22 of an air conditionerusing the inverter and battery coolant as the heating medium.

Herein, the drive motor of the hybrid vehicle is a high outputthree-phase AC motor or the like. Accordingly, the inverter whichconverts alternating current (motor side) to direct current (batteryside) and vice versa is large-size and requires water cooling becausethe switching circuit, capacitors, and the like generate heat. As forthe driving battery, a large-size battery for a driving motor is mountedseparately from the battery for vehicle-mounted electrical equipment andrequires water cooling.

The controller 28 makes control to open the first and second valves 23and 24 at the start of the engine. For the other constitution is thesame as that of Embodiments 4 and 5, the corresponding components aregiven the same reference numerals and symbols, and the descriptionthereof is omitted.

Next, the operations thereof are described.

[Heat Storing Operation]

During normal running state by engine drive, by the controller 28, thefirst and second valves 23 and 24 are opened, and the circulation pump27 is driven.

Accordingly, as shown in FIG. 31( a), hot coolant from the invertercooler 30 and battery cooler 31 passes the heat accumulator S from theinlet to the outlet and is further fed to the radiator 25 and heatercore 22. When the temperature of the coolant increases and reaches themelting point of the heat storage material, the heat storage materialchanges the phase thereof from the solid to the liquid phase and absorbsheat energy during this phase transition.

When the engine is stopped, by the controller 28, the first and secondvalves 23 and 24 are closed, and the circulation pump 27 is stopped.

Accordingly, as shown in FIG. 31( b), the coolant is enclosed in theliquid reserving portion 1 surrounded by the two layers of each of theheat-insulating layers 2, 3, and 4 and the heat storage layer 5, so thatthe temperature of the coolant stored in the heat accumulator S2 isprevented from decreasing. The coolant is therefore kept hot.

[Engine Start]

At the start of the engine (at the start of passenger compartmentheating), by the controller 28, the first and second valves 23 and 24are opened, and the circulation pump 27 is driven.

Accordingly, as shown in FIG. 31 (c), the hot engine coolant stored inthe heat accumulator S is fed to the heater core 22 during the firstcycle of the circulation cycles of the coolant. The hot coolant isaffected by the temperature of the system environment and is mixed withcold coolant. The temperature of the coolant within the heat accumulatorS therefore decreases.

However, during and after the second cycle where the temperature of theheat storage material decreases to the freezing point because of thedecrease in temperature of the coolant within the heat accumulator S,the heat storage material changes the phase thereof from the liquid tothe solid phase. The heat stored in the heat storage material isreleased during this phase transition, and the heat energy due to thelatent heat continues to be supplied to the coolant. During and afterthe second cycle, the decrease in temperature of the engine coolant isprevented by the heat released from the heat storage material, and thecoolant kept hot is fed to the heater core 22.

Next, the effects thereof are described.

The electrical equipment coolant circulation system for a drive motorincluding the heat accumulator S of Embodiment 6 can provide the effectbelow in addition to the effect (1) of Embodiment 4:

(4) The vehicle-mounted heat source includes the inverter cooler 30which heats the inverter coolant while being driven and the batterycooler 31 which heats the battery coolant while being driven. Thevehicle-mounted heat demand source includes the heater core 22 of an airconditioner using the inverter and battery coolant as the heatingmedium. The controller 28 makes control to open the first and secondvalves 23 and 24 at the start of the engine. Accordingly, it is possibleto achieve an expected increase in passenger compartment heatingperformance at the start of the engine.

Embodiment 7

Embodiment 7 is an example of, in the electrical equipment coolantcirculation system for a drive motor including the heat accumulator S ofEmbodiment 6, further including a pump 29 for the circuit connecting thesecond valve 24 and heater core 22.

First, the constitution thereof is described.

FIG. 32 is a coolant circulation circuit diagram showing an electricalequipment coolant circulation system for a drive motor (an example ofthe vehicle-mounted thermal system) including the heat accumulator S ofEmbodiment 7.

In Embodiment 7, the vehicle-mounted heat source includes the invertercooler 30 which heats the inverter coolant while being driven and thebattery cooler 31 which heats the battery coolant while being driven.The vehicle-mounted heat demand source includes the heater core 22 of anair conditioner using the inverter and battery coolant as the heatingmedium.

The circuit connecting the second valve 24 and heater core 22 isprovided with the pump 29. The controller 28 makes control at the startof the engine 21 to open the first and second valves 23 and 24 at thestart of the engine and activate the pump 29 to regulate the rate offlow from the heat accumulator S to the heater core 22. Since the otherconstitution is the same as that of Embodiment 4, correspondingcomponents are given the same reference numerals and symbols, and thedescription thereof is omitted.

Next, the operations thereof are described.

[Heat Storing Operation]

During normal running state where one of the engine and motor is beingdriven, by the controller 28, the first and second valves 23 and 24 areopened; and circulation pump 27 are driven. Moreover, during use of theheater, the pump is driven.

Accordingly, as shown in FIG. 33( a), hot coolant from the inverter andbattery coolers 30 and 31 passes the heat accumulator S from the inletto the outlet and is further fed to the radiator 25 and to the heatercore 22 during use of the heater. When the temperature of the enginecoolant increases and reaches the melting point of the heat storagematerial, the heat storage material changes the phase thereof from thesolid to the liquid phase and absorbs heat energy during this phasetransition.

When the engine then stops, by the controller 28, the first and secondvalves 23 and 24 are closed, and the pump 29 and circulation pump 27 arestopped.

Accordingly, as shown in FIG. 33 (b), the coolant is enclosed in theliquid reserving portion 1 surrounded by the two layers of each of theheat-insulating layers 2, 3, and 4 and the heat storage layer 5. Thetemperature of the engine coolant stored in the heat accumulator S istherefore prevented from decreasing, and the engine coolant is kept hot.

[Engine Start]

At the start of the engine (at the start of passenger compartmentheating), by the controller 28, the first and second valves 23 and 24are opened; the circulation pump 27 is driven; and the pump 29 is drivenfor regulating the flow rate.

Accordingly, as shown in FIG. 33 (c), the hot coolant stored in the heataccumulator S is fed to the heater core 22 through the pump 29 duringthe first cycle of the circulation cycles of the coolant. The hotcoolant is affected by the temperature of the system environment and ismixed with cold coolant. The temperature of the coolant within the heataccumulator S therefore decreases.

However, during and after the second cycle where the temperature of theheat storage material decreases to the freezing point because of thedecrease in temperature of the coolant within the heat accumulator S,the heat storage material changes the phase thereof from the liquid tothe solid phase. The heat stored in the heat storage material isreleased during this phase transition, and the heat energy due to thelatent heat continues to be supplied to the coolant. During and afterthe second cycle, the decrease in temperature of the engine coolant isprevented by the heat released from the heat storage material, and thecoolant kept hot is fed to the heater core 22 through the pump 29regulating the flow rate.

Next, the effects thereof are described.

The electrical equipment coolant circulation system for a drive motorincluding the heat accumulator S of Embodiment 7 can provide the effectbelow in addition to the effect (1) of Embodiment 4:

(5) The vehicle-mounted heat source includes the inverter cooler 30which heats the inverter coolant while being driven and the batterycooler 31 which heats the battery coolant while being driven. Thevehicle-mounted heat demand source includes the heater core 22 of an airconditioner using the inverter and battery coolant as the heatingmedium. The circuit connecting the second valve 24 and the heater core22 is provided with the pump 29. Furthermore, at the start of theengine, the controller 28 opens the first and second valves 23 and 24and activates the pump 29 to regulate the rate of flow from the heataccumulate S to the heater core 22. Accordingly, it is possible toachieve an expected increase in passenger compartment heatingperformance at the start of the engine of the hybrid vehicle and controlthe heating performance by regulating the flow rate.

Hereinabove, the heat accumulator of the present invention, the methodof manufacturing the heat accumulator, and the vehicle-mounted thermalsystem including the same are described based on Embodiments 1 to 7.However, the specific constitution is not limited to these embodiments,and various changes, additions, and the like can be made for the designwithout departing from the scope of the present invention according toclaims.

Embodiments 1 and 2 show the examples where the plurality of tankconstituting elements are stacked facing alternate directions, but theplurality of tank constituting elements are stacked facing a samedirection. Moreover, in Embodiments 1 and 2, the inlet and outlet covermembers and tank constituting elements are the constituent parts.However, the cover members may be omitted if the tank constitutingelements are configured to have such a cross-sectional shape that allowsthe tank constituting elements to serve as the cover members. In otherwords, such a heat accumulator that includes the liquid reservingportion and heat-insulating layer formed by stacking the plurality oftank constituting elements composed of plate members of an identicalcross-sectional shape is included in the present invention.

In Embodiment 2, the heat storage material is the paraffin material butmay be another heat storage material such as polyethylene glycol whosephase transition temperature can be set according to the degree ofpolymerization or inorganic salt hydrate/aqueous solution with a widerange of phase transition temperature (for example, sodium acetate,sodium acetate mixture, calcium chloride hexahydrate, or the like).

In Embodiment 2, the heat storage material includes the paraffincapsules including the paraffin material encapsulated in sphericalcoatings as microcapsules. However, the heat storage material may be onesubjected to another treatment/processing as follows: the heat storagematerial may be encapsulated in a resin container to be packaged or theheat storage material may be kneaded with resin to be shaped andlaminate coated.

In the method of manufacturing the heat accumulator, the shapes of theconstituent parts constituting the heat accumulator are not limited tothe shapes shown in Embodiments 1 to 3 and may be varied according tothe structure type of the heat accumulator. Moreover, in the temporaryassembly process, the processed constituent parts may be assembled oneafter another into a container form without the sub-assembly process. Inother words, the manufacturing method including at least: the partprocessing process to process the constituent parts constituting theheat accumulator; the temporary assembly process to assemble theprocessed constituent parts into a container; and the brazing process toevacuate the temporarily assembled container in a furnace and increasethe temperature thereof to braze the constituent parts into a unit inthe vacuum atmosphere is included in the present invention.

INDUSTRIAL AVAILABILITY

Embodiments 1 and 2 show the examples of the application of the heataccumulator using water as the heat medium, but the heat medium may beliquid other than water. Moreover, the above embodiments show theexamples of the application of the engine coolant circulation system ofan engine vehicle and the electrical equipment coolant circulationsystem for a drive motor of a hybrid vehicle. The present invention canbe also applied to heat accumulators for various purposes other thanvehicles.

Embodiment 1 shows the example of the method of manufacturing thestacking-type heat accumulator including the liquid reserving portionand vacuum heat-insulating layer, and Embodiment 2 shows the example ofthe method of manufacturing the stacking-type heat accumulator includingthe liquid reserving portion, heat storage layer, and vacuumheat-insulating layer. Embodiment 3 shows the example of the method ofmanufacturing the multi-container heat accumulator including the liquidreserving portion, heat storage layer, and vacuum heat-insulating layer.However, the present invention can be applied to a method ofmanufacturing a multi-container heat accumulator including a liquidreserving portion and a vacuum heat-insulating layer. In other words,the present invention can be applied to a method of manufacturing a heataccumulator including at least a liquid reserving portion and a vacuumheat-insulating layer.

Embodiments 4 and 5 show the examples of the engine coolant circulationsystem of an engine vehicle as the vehicle-mounted heat system; andEmbodiments 6 and 7 show the examples of the electrical equipmentcoolant circulation system for a drive motor of a hybrid vehicle as thevehicle-mounted heat system. The present invention can be also appliedto an electrical equipment coolant circulation system for a drive motorof an electrical vehicle and the like. In other words, the presentinvention can be applied to a vehicle-mounted thermal system in whichthe vehicle-mounted heat source which heats the heat medium while apower unit is being driven and the vehicle-mounted demand source whichrequires hot heat medium when the power unit starts from the power unitstopped state where the temperature of the heat medium decreases areconnected through the heat medium circuit.

1-22. (canceled)
 23. A heat accumulator, comprising: a liquid reservingportion; a heat-insulating layer provided on an outer periphery of theliquid reserving portion; a plurality of stacked tank constitutingelements configured to form the liquid reserving portion and theheat-insulating layer, the tank constituting elements being formed byplate members of an identical cross-sectional shape; an inlet coverplate provided at an inlet of the stacked tank constituting elements andto which an inlet pipe is connected; and an outlet cover plate providedat an outlet of the stacked tank constituting elements and to which anoutlet pipe is connected, each of the tank constituting elementsincluding first and second partition walls which are coaxially arrangedand a heat-insulating layer space formed between the first and secondpartition walls, the liquid reserving portion being formed by a liquidreserving portion space surrounded by the second partition wall of eachof the plurality of tank constituting elements stacked, theheat-insulating layer being formed by the heat-insulating layer spaceswhich are made to communicate by stacking the tank constituting elementsand are evacuated. a brazing fill material which is warmed underevacuation being provided between at least adjacent tank constitutingelements.
 24. The heat accumulator according to claim 23, furthercomprising: a heat storage layer between the liquid reserving portionand the heat-insulating layer, the heat storage layer being filled witha heat storage material absorbing and releasing heat along with itsphase transition between liquid and solid phases.
 25. The heataccumulator according to claim 24, wherein the heat storage materialincludes, as a latent heat storage material, a paraffin material storingheat of fusion during its phase transition from the solid to liquidphase in a temperature range not lower than a melting point andreleasing heat of solidification during its phase transition from theliquid to solid phase in a temperature range not higher than a freezingpoint.
 26. The heat accumulator according to claim 25, wherein the heatstorage material is paraffin capsules including the paraffin materialencapsulated in spherical coatings as microcapsules, and the heatstorage layer is filed with aggregates of the paraffin capsules takingan account of a change in volume during the phase transition between theliquid and solid phases.
 27. The heat accumulator according to claim 24,further comprising as constituent parts: an inlet end plate, an inletcover plate, an outlet end plate, an outlet cover plate, and the tankconstituting elements, the heat accumulator characterized in that aninlet pipe is fixed to at least any one of the inlet cover and endplates, an outlet pipe is fixed to at least any one of the outlet coverand end plates, and an inner rib protruding in a direction orthogonal toa flow of a heat medium from an inlet to an outlet is formed on apartition wall separating the liquid reserving portion space of each ofthe tank constituting elements.
 28. The heat accumulator according toclaim 24, wherein each of the tank constituting elements includes first,second, and third partition walls coaxially arranged; a heat-insulatinglayer space is formed between the first and second partition walls; aheat storage layer space is formed between the second and thirdpartition walls; and a liquid reserving portion space is surrounded bythe third partition wall, the plurality of tank constituting elementsare stacked with openings of the stacked tank constituting elements atboth ends closed with the inlet and outlet cover plates to constitute acontainer, the liquid reserving portion is composed of the liquidreserving portion spaces made to communicate by stacking the tankconstituting elements, the heat-insulating layer is composed of theheat-insulating layer spaces which are made to communicate by stackingthe tank constituting elements and are evacuated, and the heat storagelayer composed of the heat storage layer spaces made to communicate bystacking the tank constituting elements.
 29. The heat accumulatoraccording to claim 24, wherein the heat accumulator is manufactured by:stacking the plurality of tank constituting elements with brazing fillermetal applied thereto; closing the openings of the stacked tankconstituting elements at the both ends with the inlet and outlet coverplates to temporarily assemble a container; evacuating the temporarilyassembled container in a furnace and increasing the temperature of thefurnace for vacuum brazing to evacuate both the heat-insulating layerand heat storage layer; and then filling the evacuated heat storagelayer with the heat storage material by vacuum suction.
 30. A method ofmanufacturing a heat accumulator including a vacuum heat-insulatinglayer at the outer periphery of a liquid reserving portion, comprising:a part processing step of processing constituent parts constituting theheat accumulator; a temporary assembly step of assembling the processedconstituent parts into a container; and a brazing step of evacuating thetemporarily assembled container in a furnace and increasing temperatureof the furnace to braze the constituent parts into a unit in vacuumatmosphere.
 31. The method of manufacturing a heat accumulator accordingto claim 30, wherein the heat accumulator includes the vacuumheat-insulating layer at the outer periphery of the liquid reservingportion, in the part processing step, an inlet cover plate, an outletcover plate, and a plurality of tank constituting elements which arecomposed of plate members of an identical cross-sectional shape andwhich each have a liquid reserving portion space and a vacuumheat-insulating layer space are processed, and in the temporary assemblystep, the plurality of tank constituting elements are stacked, and then,openings of the stacked tank constituting elements are closed with theinlet and outlet cover plates to form the liquid reserving portion andvacuum heat-insulating layer.
 32. The method of manufacturing a heataccumulator according to claim 31, wherein the temporary assembly stepincludes: a brazing filler metal applying step of applying brazing filermetal to the tank constituting elements; a sub-assembly step of stackingthe tank constituting elements with the brazing filler metal appliedthereto; and an assembly step of closing the openings of the stackedtank constituting elements with the inlet and outlet cover plates toconstitute a container.
 33. The method of manufacturing a heataccumulator according to claim 30, wherein the heat accumulator includesa heat storage layer and a vacuum heat-insulating layer at the outerperiphery of the liquid reserving portion, and the heat storage layer isfilled with a heat storage material absorbing and releasing heat alongwith its phase transition between liquid and solid phases, in the partprocessing step, an inlet cover plate, an outlet cover plate, and aplurality of tank constituting elements which are composed of platemembers of an identical cross-sectional shape and which each have aliquid reserving portion space, a heat storage layer space, and a vacuumheat-insulating layer space are processed, and in the temporary assemblystep, the plurality of tank constituting elements are stacked, and then,openings of the stacked tank constituting elements are closed with theinlet and outlet cover plates to form the liquid reserving portion, heatstorage layer, and vacuum heat-insulating layer.
 34. The method ofmanufacturing a heat accumulator according to claim 33, wherein airgrooves are provided at joint portions in joint surfaces of the stackedtank constituting elements, each joint portion connecting the liquidreserving portion space and the vacuum heat-insulating space with theheat storage layer space interposed therebetween, and in the brazingstep, at evacuation in the furnace, the liquid reserving portion spacesand the respective vacuum heat insulating layer spaces are allowed tocommunicate with each other through the air grooves and, at brazing byincreasing the temperature of the furnace, the air grooves are filledwith the brazing filler metal by capillary to close the air grooves. 35.The method of manufacturing a heat accumulator according to claim 33,wherein in the brazing step, the heat storage layer is evacuatedtogether with the vacuum heat-insulating layer to lower than atmosphericpressure at the end of the process, and the method further comprises,after the brazing step, a heat storage material encapsulation step offilling the evacuated heat storage layer with the heat storage materialby vacuum suction and then sealing a portion through which the heatstorage material is filled in.
 36. The method of manufacturing a heataccumulator according to claim 35, wherein a thin-wall portion madethinner than a standard thickness is formed in a heat storage materialencapsulation port formed in any one of the inlet and outlet members,and in the heat storage material encapsulation step, a tip of aninjector charged with the heat storage material is inserted into theheat storage material encapsulation port to break through the thin-wallportion to suck the heat storage material into the heat storage layer byvacuum suction force, and then, a cap is inserted into and engaged withthe broken heat storage material encapsulation port to close the brokenheat storage material encapsulation port.
 37. The method ofmanufacturing a heat accumulator according to claim 30, wherein the heataccumulator includes a heat storage layer and a vacuum heat-insulatinglayer at the outer periphery of a liquid reserving portion, the heatstorage layer being filled with a heat storage material absorbing andreleasing heat along with its phase transition between liquid and solidphases, in the part processing step, an inlet plate member, an outletplate member, and three cylindrical members forming the liquid reservingportion, heat storage layer, and vacuum heat-insulating layer areprocessed, and in the temporary assembly step, the three cylindricalmembers are assembled in a coaxial fashion, and then, openings thereofare closed with the inlet and outlet plate members to form the liquidreserving portion, heat storage layer, and vacuum heat-insulating layer.38. A vehicle-mounted thermal system including a heat accumulator, thevehicle-mounted thermal system comprising: a vehicle-mounted heat sourceheating a heat medium while a power unit is being driven; avehicle-mounted heat demand source requiring a hot heat medium when thepower unit starts from a stopped state where temperature of the heatmedium decreases; and a heat medium circuit connecting thevehicle-mounted heat source and the vehicle-mounted heat demand source,characterized in that the heat medium circuit is provided with the heataccumulator whose inlet is connected to the vehicle-mounted heat sourceand whose outlet is connected to the vehicle-mounted heat demand source,the heat accumulator includes a heat storage layer between a liquidreserving portion and a heat-insulating layer, the heat storage layerbeing filled with a heat storage material absorbing and releasing heatalong with its phase transition between liquid and solid phases, acircuit connecting the vehicle-mounted heat source and the inlet of theheat accumulator is provided with a first valve, a circuit connectingthe vehicle-mounted heat demand source and the outlet of the heataccumulator is provided with a second valve, and the heat accumulatorincludes heat medium circulation control means which opens the first andsecond valves while the power unit is being driven; closes the first andsecond valves when the power unit stops; and opens the first and secondvalves when the power unit starts.
 39. The vehicle-mounted heat systemincluding the heat accumulator according to claim 38, wherein thevehicle-mounted heat source is an engine heating coolant while beingdriven, the heat-mounted heat demand source is the engine allowingtemperature of coolant to decrease while being stopped and a heater coreof an air conditioner using the engine coolant as a heating medium, theheat medium circulation control means opens the second valve to theengine at the start of the engine when engine warm-up has priority andopens the second valve to the heater core at the start of the enginewhen passenger compartment heating has priority.
 40. The vehicle-mountedheat system including the heat accumulator according to claim 38,characterized in that the vehicle-mounted heat source is an engineheating coolant while being driven, the heat-mounted heat demand sourceis the engine allowing temperature of coolant to decrease while beingstopped and a heater core of an air conditioner using the engine coolantas a heating medium, a circuit connecting the second valve and theheater core is provided with a pump, the heat medium circulation controlmeans opens the second valve to the engine at the start of the enginewhen engine warm-up has priority, and the heat medium circulationcontrol means opens the second valve to the heater core and activate thepump to regulate a rate of flow from the heat accumulator to the heatercore at the start of the engine when passenger compartment heating haspriority.
 41. The vehicle-mounted heat system including the heataccumulator according to claim 38, wherein the vehicle-mounted heatsource is an inverter cooler heating inverter coolant while being drivenand a battery cooler heating battery coolant while being driven, theheat-mounted heat demand source is a heater core of an air conditionerusing the inverter and battery coolant as a heating medium, and the heatmedium circulation control means opens the first and second valves atthe start of an engine.
 42. The vehicle-mounted heat system includingthe heat accumulator according to claim 38, wherein the vehicle-mountedheat source is an inverter cooler heating inverter coolant while beingdriven and a battery cooler heating battery coolant while being driven,the heat-mounted heat demand source is a heater core of an airconditioner using the inverter and battery coolant as a heating medium,a circuit connecting the second valve and the heater core is providedwith a pump, and the heat medium circulation control means opens thefirst and second valves and activates the pump to regulate a rate offlow from the heat accumulator to the heater core at the start of anengine.